I think "X-Treme X-Men" has some potential coming from the first issue. While I am not a big fan of over working multiverse stuff into the main titles, i think creating a side story exploring the concept is pretty nifty, even if they at already doing it in a couple other books. As far as characters are concerned, the alternates are pretty similar to their main world selves. Wolverine is less brash, and Nightcrawler is a tween, but Xavier and Frost are pretty much carbon copies. #1 is not great, but I think the series could pick up in a couple issues since #1 is filled mostly with fights and loose premise building. If you like your X-Men with some added dimension hopping, that's the whole premise, pick up the first issue and see what you think.