Among the things it's cluttered with are frozen corpses of climbers. I think one of the victims of the disaster described in the book Into Thin Air is still sitting right by the trail in freeze-dried condition.
Here’s a guy who had a 50% success rate:
http://news.nationalgeographic.com/news/2002/09/0927_020927_siffredi.html
I was also suprised to find out that Everest is really not a technical climb. It's more a really rigorous hike. Not that I mean to belittle the accomplishment in any way. But K2 is a much harder "climb" than Everest. As is Denali, so I'm told.