Spider-Man TAS was very well animated and a great series altogether. Some episodes were kinda weak and some downright
awful but most of it was great and it still stands as one of the best marvel cartoons in my opinion.
Batman, well... I think the reason I didn't get into it very much as a kid was because I found it too dark or something. I just didn't get into Batman until I got older.
X-Men. I saw awfully little X-men even though I liked the cartoon. Not sure why.
Fantastic Four: World's Greatest Heroes was enjoyable. For some reason it was cancelled.
The character designs kinda irked me at first.
It has some great action scenes, like in
hard knocks for instance but I also enjoy it because it's humorous. Like when the four accidently shrink themselves and Ben decides to make the biggest sandwich ever.
As for the bad ones...
Well, I've only seen one episode of The Avengers: United They Stand and felt like I had to throw up. The character designs and design overall was just awfull. It was also kinda boring.
Iron Man was terrible but it gave you a good laugh. It was so bad that it's funny. Of course I'm referring to the first season.
The series starts of with Mandarin who wants an undead russian zombie army at his bidding even though he has like 10 lackeys at his side from the very beginning who are not even introduced.
Iron Man gets burned by Fin Fang Foom under water and his sidekicks who can breathe under water for some reason comes to save him. They also have a tendancy to dress as super heroes when they're not even on super hero business.
It ends with Titanium Man who we don't know anything about appearing and gets his ass kicked as fast as quickly as he was introduced.
Then the Fantastic Four cartoon from the 90s was just so bad it wasn't funny.
It sported horrible animation and boring episodes.
For those of you brave enough I present to you
The Human Torch Rap.
And that's all I can think of for now.