Yeah, I don't think I've ever heard a good thing about United They Stand.
What about the Iron Man and Incredible Hulk series from that era? I've never really heard much about them.
From the bit I've seen and what I've read, the 90s Iron Man cartoon has the same problem as the 90s FF cartoon, in that the first 13 episodes are pretty much garbage, but the second half gets a lot better. Hulk I don't know much about, except I wasn't super impressed by the first episode, and She-Hulk becomes a regular in the second half of the series.