Flow every single year improves their bindings. Sometimes they improve drastically. Comparing a pair of 2005 Flows to a 2010 and above is like comparing two totally different bindings from different companies with the only similarity being the look.
Flows used to be tank heavy. That is no longer the case. WiredSport posted weights for various bindings in comparison and Flow was as light as most. Even then, it was heavier by a negligible difference.
I had the '05 Flite 3, '06(?) Pro FS, and the '10 NXT FSE. The FSE's were badass. Very light and responsive. The only reason I don't ride Flows currently is because of canting. My left knee is starting to give me problems and cant beds really help out. I wish Flow would get canting, but they said they have to get rid of their rocker baseplate if they do that.
Also, Flow has had mini ratchets for the past few seasons. I believe they started that in '09? Basically, they are smaller versions of traditional ratchets. You can unstrap the cap in deep powder situations and strap in like you would with normal bindings. Just undo the outer two ratchets. The SE versions of Flows only have two outer ratchets because the inner two ladders are tool-less adjustments just like traditional bindings.
In my experience, Flow gives you the best edge to edge response. This is just an inherent quality of the cap design. You can really drive into those edges too. What Flow lacks though is lateral flex of traditional bindings. This is why many people feel that Flows aren't as responsive, particularly freestylers. This is the reason I prefer traditional bindings for freestyle riding. But hey, Scotty Lago does fine (for what it's worth ha).
I recommend Flows if you get pressure points on your foot from traditional bindings. Flow distributes this pressure evenly on the top of your boot so it practically eliminates foot fatigue.
Another benefit is the easy of entry (outside of powder situations). Not because you're going to get in 10 more runs, but because you won't be bending down as long to strap in. Really great for small hills.
If you are doing riding that involves cliff drops and deep powder, I really don't think the 5 is right for you. I'd at least get the AT/ATSE and above. If all you do is freeride like that, then the FRX is the binding for you. The FSE is great for all-mountain riding as well.
One word of caution with Flow bindings... they have more moving parts. That means there are more chances for failure. It's important to check your bindings regularly. I was checking my Flows every time I completely unstrapped. Takes seconds. Contact Flow and request spare hardware and bring that with you on the mountain. The most that has ever happened to me with even my '05 Flites were things like loosening screws. Easy fix with a pocket tool.
Also, the point about the tightness of Flow's cap. You really don't need to crank them down like you do with your traditional straps. Yes, this definitely feels odd at first. Hell, even when you have them cranked down, you're going to have this awkward feeling for a few runs coming off traditional bindings. My first switch to Flows had me falling like I was a noob again. Once I got the learning curve down... beautiful.
You'll also eventually learn techniques to kick in easier. I was able to have my caps fairly tight and still kicked in easy. I was also at the point where I could kick in while skating off the lift. Even kick in at an incline. Definitely takes time to learn all the little tricks like that. No doubt Flows also take a long time to set up and dial in properly. If you're lazy, they might not be the best option.
And yes, they do create wear on your boots. Mainly on the back of the boot in the heel area. This is due to the highbacks constantly rubbing on them as you lock up. This is why Flow boots have this harder rubber on this area.
Sorry for the dissertation. As a long time Flow user, I have a lot to say about their bindings