Probably wouldn't play this if I wasn't such a strong TMNT fan
Personally from a price point of view, I think they've done a good job but there is a feel of cheapness when you play it due to what I could call junior programming bugs.
The voice acting was actually quite good for the turtles - except for Raph, didn't sound like a teenager to me! They look really good, nice to see some realism for a change. It's nice to hear Splinter sounding like the 2003 cartoon series too.
Big kudos for letting Shredder stick on as Japanese decent (MIchael Bay - you suck!).
In terms of the game, I am enjoying it but the game feel very clumsy. Unfortunately I am comparing to the high quality and class of the Batman Arkham series but that is to be expected when they're ripped off their system to such an extent. Multiplayer is odd... I find myself teleporting and hitting targets that have already been defeated because of the lag. I had this issue with Ghostbusters too - Red Fly, you need to work on this!
Overall, I would say to buy this game of you are a true TMNT fan but be prepared to be disappointed in some areas as it is a cheap game and doesn't have the refinement that you would expect in a retail game.
Edit: After playing this a little longer, I've come to enjoy it more as leveling up the turtles makes the game play better. Worth the money for $15!