I liked it in Lost Planet. It's pretty cool that they have a character model that unlocks at lv.85 or something, with patterns unlocked for him later, and he did look bad-ass. The same goes for Lost Planet: Colonies, at lv.100 you got a Frank West model, and at lv.130 you got a robot, with patterns being unlocked for it later.
I like that, it's purely aesthetic and doesn't benefit the player in any way (unless the guy he goes up against shits it because he's being chased by a robot). I like being given cool shit for stuff I do, even if it doesn't benefit me statistically.