It depends on your preferences. I'd never tell someone NOT to experience an attraction, at least once, but personally I've seen L!M!A! once and that was enough. It's slow moving, cheesy (the whole "we're pretending to make a movie" thing gets old quick - it's 2005, we know better, LOL) and really only one or two stunts of note. It's also very loud.
That said, many, many people enjoy it. I would try to fit it in - but on the other hand, I wouldn't think you'd be crushed if you can't. The best part of the attraction for me was the view from the top - you can see many WDW landmarks (GMR, Swan/Dolphin, SSE) from up there.
N.E.D.