Should have made this poll a multiple choice one.
Beast has always made a better Avenger than an X-Person to me. Heck, I liked him better as a Defender.
But he's not the only one:
- Storm
- Nightcrawler
- Shadowcat
- Iceman
- Colossus
- Rogue
and many others would make excellent Avengers.
Nope. X-Men is X-Men. X-Factor ain't.