I'm always excited to see someone interested in using Shulk-- please, do give him a try! The only thing I'd forewarn you about is the promise of 'combo potential' with him. While he is an incredibly fun and technical character to use, his gameplay is not focused on long combos or strings. He's focused on using his excellent spacing tools and Monado Arts to gain stage advantage by walling out his opponents, and can dominate while in the advantage by maximizing on a given Art, being covering multiple options from your opponent at once, make punishes absolutely soul-crushing... you get the idea. While he doesn't have a plethora of true combos, and most of them are only two or three hits, his advanced techniques increase their utility and efficacy (and, at times, are the only reason they are true at all).
And, like Mace said, he is a character that (much like how you described Dante, although I also don't play UMvC3) requires much time and dedication before you can even think of succeeding with him. He's got a high learning curve, and unfortunately has some rather lacklustre qualities that can make his disadvantaged state... well, fatal. But using him will also help you to become an impeccable player, as you learn to both strategize for MUs before the match begins as well as adapt to different play styles mid-game in a way that no other character can do.
If you have any specific questions about Shulk in competitive play, how he fits in the current meta game, or whatnot, you can probably find some folks over at the
Metagame Discussion to help out.