I own a pair of last years GNU Choice and I actually liked them a lot.
I was looking to go with the speed entry system and looked at all different types before I made my purchase. It came down to GNU and Flow for me and since i had ridden with a toe cap the year before and really loved it, i went with GNU and figured that if they didn't work out I would just get Flows this year.
Out of the box, they do seem like they are a bit tedious to setup, but once you realize what you're looking at, it's actually quite simple. Took me maybe 10 - 15 minutes to get everything set to the right tensions and angles.
Though last year was almost a complete waste, I still got out a good amount and found myself really liking the bindings. I do prefer a stiffer binding, even in the park, and these worked just fine for me. I never had an issue with getting in and out of them at all. I do know what you guys are all talking about with the adjusting of the end cap a lot. I did this a lot in the very beginning of using them, but as i rode them more i realized that the placement of the end cap didn't really matter because of the angle that they come up from the board and then go around the boot. Any lifting of the toe just resulted in the strap pulling down tighter. Towards the end of the year I don't think i had to readjust anything on my bindings at all. I went weeks without so much as tightening an ankle strap. That's pretty significant.
Had the 2013 Flows with the new system that includes the end caps been out at the time I may have gone with them, but they weren't, so I didn't. I'm happy with the Choice and will ride them again this year as long as nothing breaks out of nowhere.
Hopefully one of my friends will get the new Flows and I can compare.