Personally, I'm a huge fan. I don't listen to the criticisms, and many of the things that those critics don't like are exactly the same things that I think makes WAR is so good. Not every piece of work of his is genius, but I've got a pretty nice digital collection that I've accumulated on my hard drive over the years---about 250 works, from his website, from the Paizo website, and from the WotC website mostly---and by and large, I think they rank among the most exciting fantasy art I've got.
This piece, from the Paizo website, is a pretty recent one, and it highlights his style; both the positive and the negative, and is a darn good piece of work in my opinion. Ladies and gentlemen, the mean streets of Absolom!
I take a lot of the "vibe" of WAR and really want to incorporate that into my games. I think his "vibe" is very compatible with the pulp aesthetic. It's never sitting still; always in motion, always exciting; it's action written in ALL CAPITAL LETTERS, BY JOVE!, it's exotic and "k3wl" characters, it's fantastic environments, it's classic and yet modern at the same time.