I was never into Transformers much. I was He-Man when I was really small and then GI Joe until my teens.
GOT TO GET TOUGH, YO JOE!
He-Man has aged really poorly though. I tried to watch a few episodes not too long ago, and no nostalgia glasses in the world could save that thing. GI Joe fared a bit better, but still not well. Transformers, well season 1 was entertaining, but then it just went downhill from there (the animated movie is still awesome though), but what really saves Transformers is its awesome comic, which seemed to grow with its audience. The earlier ones were rather childish, and they did not seem to dare to do anything outlandish, but in the later ones, the story lines get a lot more mature and interesting. It is still a comic for children and people in their lower teens, but it is surprisingly well written, and some storylines were quite dark (there is one set in a not so distant future, where the Decepticons have won, and hung Rodimus Prime's corpse between two buildings in a ruined city, that I think stands out. Don't know if that was from the UK or US comic, we got most of both, but they also cut some story lines for no reason here).