I haven't played it. I have seen a couple of friends enjoy the game, though. The graphics are distinctive, from what I have seen. Well, nothing like I've seen anywhere else, at least. Good gameplay, too, from what I've seen. But for me it is the artwork that stands out.
I don't know if anybody here at TS remembers the now defunct French comic magazine, "Heavy Metal". (The American edition of HM is still running strong, I think.) My older siblings were fans of that magazine and I still have a few copies here in my apartment somewhere.The overall concept, artwork and storytelling that formed the foundation of that magazine were amazing: well ahead of it's time.The graphics in Borderlands 2 seem to be heavily influenced by contributors to "Heavy Metal" -- by the French artist, Moebius, in particular. (I think his real name was Jean Giraud.) Well, at least that's my personal opinion. Others may have it otherwise, of course.
I'm almost sure the creators of the game would acknowledge the influence -- were the question ever directly posed. It's unmistakable. Or have they, already?