The advantage here is that not everything is on ELPA. Many bits are in github, or Emacswiki, or some other more random system. Using
el-getlets you easily deal with all of those things in a similar manner. The configuration options seem well-done too, though. It's a really nice system.
I played around with
el-get, and I didn't have any issues. However, I wouldn't recommend it. I think more things are moving to ELPA, and anything that isn't there is best ignored for now. When Emacs 24 is the baseline emacs people use, which should be a few years from now, I'd expect every notable package to be on ELPA. So I'd keep it simple, and ignore