I love Mushroomhead, and I thought "XX" was a terrific album. The guitars aren't anything special, but "The Head" makes up for this with the use of keyboards and samples. The drum work is pretty damn good, and the two vocalists play off of each other very well.
I wouldn't classify Mushroomhead as nu metal at all. In fact, it's hard to put them in any genre, because the disc has a little bit of almost everything. Techno, Jazz, Death Metal, Rap, etc. Hell, they even cover Pink Floyd's "Empty Spaces." It's pretty damn good too.
