Oh TVPaint?
I really love it.
I think it depends on how you like working really.
TVPaint is nice is you like that hand-drawn look that Disney movies have, Adobe Flash is nice for that vector-y, thick outlined look that Power Puff Girls and My Little Pony have. Of course you can do either style in either program but I'm more into TVPaint's big emphasis on traditional-looking drawing as opposed to Flash's emphasis on symbols.
I hope this helps! 8D