I just downloaded 2.3 (20430?) and gave it a whirl. I'm going to go back to 2.2.1 due to some game changes/bugs that detract from my fun.
Although I was originally weirded out by the way reaction fire works in 2.2.1, after going back to the old X-COM way of doing things in 2.3 I think I have to say that the former was better. When your reaction fire has to come out of your current turn, you lose the TUs whether there ends up being anything to shoot at or not. This REALLY slows down the gameplay and be very frustrating, making it difficult to get into any kind of a tactical position. My machine gun guy can only take 1 step/turn if he wants to crouch afterward.
I DO like the option of reserving fire separate from reaction fire, and reserving crouching was a nice touch too. I don't think crouching should cost more than a standard step though.
I wanted to say that the new way is more realistic, but the more I think about it, it's really not. Picture yourself walking down a spooky hallway with a gun in your hand, waiting for an alien to pop out. You might lose some TUs by "being cautious", but if nothing pops out, you're not slowed that much. Then let's say an alien comes around the corner - you snap your gun up, blast a few rounds in him and this is when your ability to perform more actions is decreased, right after jumping to action.
So basically, this is how I think would work best: reserving does use up SOME TUs (a down payment, if you will) which you lose regardless of whether you fire or not. 7 TUs from 2.2.1 worked well making you plan ahead, but still giving you options on your turn. Then if you fire, the cost of fire is taken from your next turn (perhaps a bit cheaper, since you did contribute from your previous turn). I just think this way would feel more tactical, and move things along well.
Also, in my 2.3 build my interceptor didn't seem to actually shoot at the UFO (Rotary Cannon & Sparrowhawk Missles properly installed), but merely followed him from The Mediterranean to Alaska. I do like the increased range, and not needing 4 interceptors/UFO is nice (I assume it's balanced that way since there's now only 1 ship per hangar.
I also had the texture bugs others have mentioned, but I'm sure they're being addressed.
I love this game, I was reading on its development 3 or 4 years ago before any playable releases came out, then forgot about it until now. Very impressive! I hope it keeps coming along - it has potential to be THE best tactical game ever! (if it's not already)
P.S. In 2.2.1 I seem to get nothing from having researched the stingray and dragon interceptors. Am I alone?