We camped at Lake Mead in the lower campground for 2 nights in late March. We camped there because valley of fire state park had no more spots, so we were thankful to find any place to stay! It is 10 dollars a night to camp at Lake Mead, so that is a great deal. Campground is located on a bluff overlooking the dried up portion of the lake. We hiked down to the old lake bottom and followed wild burro trails (there are some escaped donkeys that hang out in the area--and the parks are on a mission to eliminate them due to their competition for grazing land with big horn sheep). The lake bottom is cool, there are parts of old boats and other trash (excellent place to play treasure hunter, but be careful of broken glass).
Downside of the campground is that it is the windiest place we have ever camped. We were afraid the tent was going to blow away. Seriously. Bring extra tent stakes if you go, or maybe stay in the upper campground...it might be more protected, I am not sure.
The only other downside was the super loud family that camped next to us. They screamed and played with their dogs all night. Their ruckus was only trumped by the braying wild donkeys at 1 AM.