It seems like almost all of the nay-sayers in this post have zero experience on Drift Boards, so here's an honest review from someone who has 65+ days on them in all conditions, all terrain. For reference, I also have 75+ days on various split-boards. And I'm not sponsored or affiliated in any way, just a big fan and advocate.
1. Drift Boards are infinitely superior to snowshoes and to Hok skis (& similar, like GlideLites). Both of the two choices of semi-permanent skins offered on the Drift Boards provide you with much better glide than snowshoes along with WAY more grip than you get from Hok skis (which I've also demo'd). With the Drift crampon attachments, you have the ability to attack icy steeps as aggressively as you would with mountaineering snowshoes (*not that you should use them for icy steeps, see below). So, you get ski/split-board glide characteristics + steep angle grip + substantial buoyancy in pow. They should only be weighed against a split-board because that is what they aim to take the place of.
2. As much as I love them, it's worth noting that Drift Boards are NOT perfect 100% replacements for split-boards in every type of terrain or condition. The wide waist-width and lack of metal edges means that they aren't really appropriate for exposed, high-alpine tours where you expect to encounter icy crust over no-fall zones. They also aren't very comfortable for long side-hill traverses on firm snow or ice. Drift does offer a narrower version of the boards as well as a crampon attachment which would probably suffice to get you to a big summit, but if I had both to choose from, I'd opt for the extra camber, extra edge length, and extra skin square footage of my split-board for the more extreme tours. You could also make the argument that a split is the better choice for tours which require really long, really flat approaches/run outs, because it is true that a split board will glide a little better than the Drifts thanks to the camber and length (I estimate about 15% more glide in the flats, depending on board choice and conditions). This is not a factor once you are on any pitch with any upward angle. Since I hike/ride/tour in New England, I rarely encounter long, flat approaches, except for some of the resorts we often hike, but in that case the flats are always groomed and fast and perfectly suited for the Drifts. The lighter weight of the Drifts does allow for increased cadence in your step which can somewhat offset the delta in glide efficiency vs a split-board, so it's not that you should avoid flat approaches - they'll be totally fine - just that a longer board has a slight advantage in this case.
3. Once you are past the flats and moving uphill you will quickly surprise your buddies at how quick and nimble you are on your Drift Boards. I regularly tour with 3-4 split-boarders + 2-3 skiers, all highly experienced and on premium gear, and I am regularly the one breaking trail, setting the pace, and often gapping the group. My Drift Board setup is roughly half the weight of my split which means my cadence tends to be naturally faster and my leg/abs/lower body fatigue is significantly reduced. I'm hella quick stepping around or over obstacles in the very dense/tight NE forests. No more kick-turns... just quick/easy sidesteps and wiggles. My pitch angle range is significantly increased (I can go steeper) in soft snow thanks to the shorter/wider boards + heel risers, meaning I don't have to look for long, clean lines and angles. On the topic of soft snow, the float has never been an issue for me on the Drifts, even in the deepest/lightest pixie dust powder. While I may sink slightly more compared to the split-board, the ease of stepping up and out of your track & holes easily accounts for the marginal loss of buoyancy. I can't emphasize enough how much energy is saved by shifting the weight of your uphill setup from your feet (split-board) to your back (Drifts + solid). I get to the top faster and feeling fresher and so do all my buddies who have converted from Splits to Drifts. The nay-sayers in the forum above have clearly not tried the Drifts or toured with someone else on them to see how capable, efficient, and comfortable they are.
4. Related gear required with these: Yes you'll have to carry your solid board on your back. I carry a volume shifted board with a short tail, and I strap it slightly high to keep the tail edge off the back of my legs. Almost any board dedicated to power will have these advantageous dimensions. I've also seen some riders carry their solid boards horizontally or diagonally to minimize windage and overhead clearance, this seems like it would work well on open/exposed trails where wind was more of an issue than clearance around tight trees (like at a resort). My trail weight for a full-day of skinning the resort or BC touring (water, snacks, layers, safety gear, etc) in a 26L Gregory pack is about 14lbs + board. I strap it tight to avoid wiggle or slop and that system feels so comfortable that I honestly forget about it until I prepare to transition. Occasionally I tap an overhead branch with the nose of my board and get some snow down my neck, but it's a small price to pay to be able to ride my solid board downhill on fresh legs. It's also a small price to pay when weighed against the delta between the cost of Drift Boards (~$400) vs a split-board package w/ skins, bindings, interface, etc (~$1,250?). Another massive pro for the Drifts is that you don't need skins and don't ever have to transition them. Some of my worst days in the BC were caused by malfunctions with my split skins, either from them losing hardware, icing up, losing adhesion, or otherwise just being a pain in the ass. Since I ride in the bitter cold of the NE (regularly sub-zero mornings w/ windchill), it's pretty nice not to have to transition those skins or to warm them up with body heat just so that they'll stick to your base on the next yo-yo lap. Finally, to the comments about having to carry the Drifts downhill, I would encourage you to get out and try it. They weigh about 2.5lbs ea or 5lbs total, and easily strap securely to the back OR to the side of your pack. Like with my solid board uphill, I hardly notice the weight or bulk on the downhill. There are a few clever ways to rig them on various packs, the key being to eliminate any slop/wiggle. I've even carried them on tiny 15L packs which didn't have exterior straps, just used a Voile strap and voila.
Did I mention faster transitions...?
5. Details on my personal Drift setup and strategies: I have a suite of Karomorum hardware from my split-board and figured out that the fastener holes on the Drifts matches the pattern of the K interface (which also matches Voile and Spark R&D). I tried the Drifts at the resort with my K bindings + heel risers one day and loved it - the bindings are a little heavier than the universal bindings that the Drifts come with but I like the added stability around my boot, especially in the backcountry. Karokorum (and all other split bindings that I've seen) offer a quiver connector, which serve as an interface to attache your split bindings to your solid board. The K system also means I can use their heel-risers w/ heel locks, which have come in handy on a few occasions in gnarly terrain (side-stepping over something dangerous). As an added bonus, using split bindings means that I don't have to carry the weight of my resort bindings on my back for the uphill, or the weight of the Drift/universal bindings on my back for the downhill. The Drift Boards also stack & pack a little thinner/tighter without the universal bindings on them. Of course this setup is only advisable if you enjoy the feel and performance of your split bindings like I do. I prefer sliding the Drifts into the 'A-frame' straps offered on either side of my pack. This keeps the weight closer to the center of my core, keeps them riding a bit higher (so the tails don't drag in the snow if I lose edge and butt-slide), and serves as a sort of rigid external pack frame to keep the whole system super tight with minimal slop. They are wider than most skis so it is worth checking that your A-frame or side-straps can accomodate the width. The other option is stacking them together and strapping to the back of the pack. Again, with a couple of compression straps pulled tight to your back, you'll hardly notice the 5 pounds. I've even seen someone stash the boards inside of a larger pack which seemed like an awesome solution, but would only work with probably a 40L+ sized pack.
In summary, the Drifts are really really awesome tools that can offer much of the same performance that you'd get out of a split-board, in most terrain and in most conditions. They do have limitations but they are roughly a third of the price to get into vs a split package, and they offer some notable advantages in the right terrain even compared to a premium split-board. I'm not saying that they're for everyone, but if you haven't tried them yourself, or if you haven't gotten smoked uphill by a buddy on Drifts, stop poo-pooing them because you sound dumb and you're discouraging others from exploiting a super cool and super efficient piece of equipment that gets people uphill. If you just want to hike the resort + side country or BC on nice days, and are having trouble swallowing the price of a new split-board package, these are perfect. If you're an experienced split-boarder who hasn't found the perfect board yet and really misses your solid (like I did), these are perfect. If you're a crusty old grouch who likes to shit on every new idea that you come across in a forum, come hike with me at Jay Peak anytime, I'll let you demo them then buy you a beer after I beat you up and downhill.
Resort hiking/riding - 10/10
Sidecountry touring in most conditions - 10/10
Deep BC missions in powder - 10/10, unless long/flat approach then 9/10
Extreme alpine tours above treeline/no fall zones - 6/10 (doable, but not advisable)
Pow-surfing - 12/10
Happy to DM anyone who has any other questions.