The initial seasons of the Clone Wars had pretty poor animation. It improved as it went on.
I would suggest to anyone watching this show, if they don't want to get into the animated stuff altogether, at least watch the last four episodes of season 7 of the The Clone Wars (episodes 8-12). They span from just before the start of Episode III to just after, and the quality of everything in those four shows - from writing, to animation, to music, to the performances of the voice actors, is an order of magnitude above what most of the animated stuff achieves.
TCW as a series has a lot of highs and lows. I can't talk much about Rebels I guess because I quit on it pretty quickly and just watched some of the highlights, e.g.