I have only seen the first two episodes of Fast Forward, so my opinion is based on that, but I highly doubt the third one would change my mind much.
Anyway, while I don't
hate Fast Forward, I'm definitly not happy with it either.
Animation: I don't get where everybody is seeing anime vibes, no one has big eyes or sweatdrops or any other typical things from animes. It's still a far cry from Teen Titans (which I actually like). But still, it looks so flat and liveless now, the 2k3 toon was much better at shading and creating visual depth. The colors were more vibrant and everything was much more detailed (just looks at the turtles' shells).
Characters: Splinter is being downplayed a lot and seems to be reduced to some comic relief character. I also miss the rest of the old cast. I want April, Casey, Karai, Leaterhead, the Fugitoid and all the others. Not some kid that is only there so the target group of the show can project themselves in his place. And Starla (?) smells like love interest for Cody and required female for the girls that might watch and so no one can complain that they lack female characters. The whole "Look at me, I'm smart, cute
and have rollerblades" really put me off the charcter. And Cody is shaping up to be a big Gary Stu.
Plot: Well, I can't say much about it now since the series just started, but the whole "Darius the evil uncle" storyline doesn't exactly put me at the edge of my seat. I expect some "shocking" revelation for Cody complete with "How could you? I trusted you!" Booooring.

Hopefully this 'Dark TMNT' thing people keep talking about turns out better.
In conclusion, I'll give it a chance, but I'm neither thrilled right now nor do I'll get my hopes up too high.