In decreasing order of brilliance, the only Transformers cartoons worth watching are:

Beast Wars,
Animated,
Beast Machines,
Masterforce and
Car Robots/Robots In Disguise.

Avoid the rest. And seriously, if you haven't watched Beast Wars, it should be leagues above everything else in the world on your 'to watch' list. I'm envious that you even have the chance to experience it for the first time, which - unless I get Alzheimers or something - is something I'll never be able to do again. It continues on from G1 continuity and is the best animated series Transformers has ever had. (And probably ever will have.) It won an Emmy. Watch it.

(In my opinion. Obviously.)