It's a not a bad title, but admittedly it is somewhat repetitive. The game is pretty short, so you'll have to play through it three times with all characters if you want to get the most out of it.
All in all it's a neat action RPG with a few good ideas. I think even the $5 price tag is a bit steep considering what you get, personally, but it's one of the few titles on the Live service that I could say actually stands out to some degree.
If you're hankering for an action RPG, it's really your best (and kind of only...) option, and this is as cheap as it's likely to be for a while. Why don't you just try the demo and see for yourself how you feel?