I played the game for the first time last night, here’s what I noticed. This was all live match stuff, I didn’t have the opportunity to go into training mode…
The game is slightly sped up. It was throwing off my combos, but I only got 6 matches again, and no time to do training mode, so everything was done live and had to adjust on the fly… Trying DP FADC CW got messed up everytime for me, so I’ll have to practice the new timing. The CW wouldn’t come out, so I must have been doing the input too fast, thinking I needed to be faster than I had to probably. I was playing on a different TV than I was accustomed to as well, but I didn’t notice any lag whatsoever so it doesn’t seem to factor in. You just gotta learn the new feeling of the game.
Fei’s dash does seem improved, but I was still mainly using rekka pressure to move forward, so I didn’t use the dash too much.
RH CW is much much faster now, as it was in vanilla SFIV. Maybe faster? It’s been so long since the patch, but I was very happy with the speed. I didn’t try to go through fireballs with it, I just used EX out of habit. CWs were always easy for me to do, so I didn’t notice if teh controls changed. At least you can keep doing them the old way if you want to.
F+RH is indeed quick as hell. No one’s going to focus you out of it if the first hit connects. I’m sure there’s new things we can think up to do with this. I didn’t try linking cr.lp after like someone mentioned.
Wakeup DP seems to have better auto-correct now, I was nailing crossups quite a bit more often with it. Even CWs were turning into them, but I know this was kind of the thing to do in SFIV (do a CW and you might get a DP, or escape with CW). But trying to DP would result in a auto-corrected DP on cross-ups. DP can still be stuffed by some jump-ins from what I experienced.
With the new speed, it was again a little bit harder to land that 3rd or 2nd rekka, you’re going to have to speed up your inputs. Practice will help you adjust to this.
I read somewhere his normals were adjusted, made fractionally faster. Felt that way, but coulda been the adjusted game speed. As I said earlier, timing on combos/links is changed (not sure about frames, but definitely real world speed), and if you want to do a cl.HP to rekkas, you better do it faster than you’re used to.
I like to do backthrow, fake or empty crossup into Tenshin, and let the controller be neutral. I was doing more flame kicks on landing than I liked, and they whiffed since I was punished. When a tenshin did come out, it landed successfully, but read below…
Had some difficulty pulling off cl.HP/MP xx rekkas after Tenshin. I normally plink HP and MP together and then do rekkas, but this wasn’t rekka cancelling for me for more than half the time. Again, must get used to timing again.
Gief’s jump is higher, so him doing his belly flop crossups on wakeup isn’t as successful. My DPs seemed to auto-correct a lot more which of course helps a ton, no more getting hit on the useless backside of the DP. I beat my friend’s Gief, though while not his main, he is good at pretty much everyone so I was quite happy. Gief’s lariat will whiff after the first hit when you’re ducking. In fact, my friend did the lariat just outside of first-hit range, and the move whiffed entirely. Lariat is so begging for cr.mp > super after the first hit is blocked or whiffed 
I may be too confident, but I feel this is a worthy Fei. I think he has a lot more potential to win in this version, because he’s better than he used to be and other characters were adjusted to be not as strong in some cases. I didn’t play a Guile yet, but tomorrow I probably will, and this one is very good (aegis neglector/flexo), so I’m sure I’ll get my ass kicked. If I was on Starnabs level, it’d be a fair fight.