I reviewed all my options for rear-entry bindings this season and I ended up buying the GNU Choice. I've spent half a season using them now and I love them. Essentially you have the easy entry of the K2/Flow and you also have the comfort and stability of a 2-strap design. Plus the lift hill tension release on the back strap is just brilliant. I have no problems getting into the bindings unless I'm on a really steep slope, and then I just have to face up the hill, dig my toe edge in a little bit and then lean up the gradient while I put my boot in and tighten up the bindings. I can't speak to using them in deep powder, since I'm in the midwest and it's all groomed hardpack.
These have a fixed toe cap instead of a ratchet, but I don't find it to be a problem at all. In fact I actually like them better than the toe caps on my previous Burton Customs because the Customs always slid up like crazy, even with the ratchet. The back strap has a ratchet but I never have to use it because it's a "set and forget" design. I get it to the tension I want while closed and then I don't have to touch it the rest of the season. Getting your boot out is even easier because when you pull down the highback it automatically pops the rear strap loose so you have plenty of room to slide out. These bindings are also fairly light and adjustable and when I'm riding they feel comfortable with no pressure points and just the right amount of flex.
I can't speak to the long term durability but after half a season they're still working like new. I definitely recommend them over the K2 and the current flows. When Flow comes out with their new model that has the same(ish) features as the Gnu and two strap design, I'll probably go with Flow just for the durability and reputation. But for now these bindings are awesome.