Well, since I started this thread, I should at least give some of my input into it.
Am I the only one here who liked Bioman? I had no idea so many people disliked it. :disappoin
I thought the characters, the fight scenes, music, and the special effects were pretty well done.
Like what Shougo said, Changeman was probably the most well planned season out of them all. Plus, the fact that every character, especially villains had a story going on and were very well wrapped up at the end was definitely one of the elements that made Changeman such a powerful season.
Flashman was also very well planned. And like what Aoi Kurenai said, the chemistry amongst the characters on the show was very well done (possibly the best). And yeah, Bun is probably the best example. And the villains are really cool. I especially loved Lee Keflen. He just seemed like a really well developed villain to me. And the whole bittersweet ending was just perfect.
Comparing Changeman and Flashman together, it seems like these are all probably the most powerful elements of each show, and it would depend on what the fan likes.
Maskman and Liveman both took a bit of a different approach. It seems like Changeman and Flashman's episodes all revolved around a ton of action in it's plots. Maskman and Liveman's episodes seem to be more heavily character focused rather than the action.
Turboranger seemed like it went back to the heavy action plots for it's episodes. Loved how it perfectly mixed the vehicles, fairies, and demons all together. I thought that was cool. I was quite surprised with how they handled eps 27-30. That was a huge change! Same with ep 38.