At first I thought RID sucked, but compared to the newer shows, it is very entertaining and I've grown to like it much more. Car Robots is good, but I havent't finished watching through yet. It is very different from RID, more energetic, but I don't know if that's a good thing or not.
Armada is very annoying, except for Starscream, he's cool in that series, but I'd love to watch Micron Legend.
Superlink/Energon both suck.
Cybertron: annoying voices and crappy, weightless animation. Galaxy Force at least fixes the voice problem, but, yeah... at least the story is doable.
BWII is very childish, but entertaining, haven't seen BW Neo yet.
BWII the movie is great once it gets started. Mejin Zarak, baby!
Headmasters is decent, not the best, but atleast it has G1 characters. Haven't watched Masterforce yet and Victory I've only seen in the english dub, so it's not fair for me to judge it. Original language adds so much to the show (except for RID/CR, I really don't know which I prefer).
Zone is the best episode ever... of any TV show... period

So much action, it blows your mind.
There's the rundown! My favorite would have to be RID/Car Robots. They are both good shows with simple and fluid animation.