Smut? This is relevant to my interests! Well, if you ever need another...

Energon has some interesting characters, mostly in the villains department, but the Autobots are pretty cookie-cutter and Kicker's just a flat-out dick. If you can put up with the plot being slow and going nowhere, you might like the interesting parts.

I liked Cybertron, as it at least tried to shake things up a bit with the multiple planets.