Eeee flash. xD I have, I don't like it much. Don't get me wrong, it works, but... Mmmm, here's an example.
The animation in this: [link]
is traditional animation (pencil and paper + finishes) and this: [link]
at least once you get past the opening credits, is made in flash. Flash is easier, but traditional looks so much better - it's a quantity versus quality thing.