[neatoman]

I'm not sure there's necessarily a "best" season. But the more you watch the show, the more you'll realise how needlessly slow the story is and the more tiresome the monster of the week episodes become.

But if I had to rank them, I'd say Season 1 would be the best one the problems had not yet piled up. There are still some problems, like how the villains don't really do much until the end and how some things just seem to pop up out of nowhere, like how the Technodrome is literally first mentioned in the same episode it's introduced in. But it's fairly self contained and has enough character development and story to make it feel satisfying overall, if there no more seasons after it I would have been fine with that.

Season 3 has not finished yet but it is my second favourite so far, though that could easily change. Why is it my second favourite? The Kraang are finally defeated and more focus is thus given to the Foot Clan who have basically done very little up until that point. And for more biased reasons, I just like seeing the farmhouse and Hun back in a cartoon, I will agree they probably spent too much time on the farm but it still felt nice to see it again. I don't really care that Hun looks more like Bruce Lee than the old Hun, he still felt correctly written.
But I must clarify, season 3 does still have real problems like everyone is saying.

Season 2 is my least favourite. There's too much focus on the Kraang and filler episodes, virtually nothing important happens until episode 22 and by then the season is almost over. It was also in that season the Foot Ninja were replaced by robots, and I really don't like the idea of the Foot Clan just being a bunch of robots. I don't really like that the new major villain of the season, Tiger Claw, is just Ciro Nieli's Mary Sue. It's also the season when Donnie's crush on April became really annoying. I like that Casey was introduced but he doesn't really turn into a main charcter the finale, until then he's just sort of an ally. The season generally feels like filler between seasons 1 and 2, that's just not right...