There's probably a good case study to be made here on why so many people have had bad experiences with GlusterFS. If the problem is that it's too easy to set it up in a fragile way, then they need to fix that, because otherwise you're going to end up with a lot unhappy users (as you can see in the other comments).

Still, if I can't make it work well on a reasonably small scale, why would I expect it to work any better when I scale it up?