We spent a couple days last week camping in Anza-Borrego, driving through Joshua Tree on the way home. Everyone knows Joshua Tree, and in fact the place was completely crowded, a combination of widlflowers in bloom and Spring Break. Anza-Borrego was definitely the better choice, if maybe a little subtler in its colorful offerings.
Here's a palm oasis we hiked to in the southern portion of Anza-Borrego:
And here's a scene from a cholla cactus grove at Joshua Tree:
Love the desert, and wish we could have stayed longer.