Didn't know about this one. There's quite a few labs/sandbox SaaS but what I've seen so far is that they are more for training with a "follow the recipe" model (do this do that to configure something, rather than "this (real) server is broken, fix it (with possibly different solutions)" which imho is more real-life and useful.
I believe the company was founded by some coworkers of mine way back when at Rackspace who often interviewed Linux admins with a lab VM and I assume they just automated the setup and spun it off as their own business. At least that's what happened as far as I can tell; I didn't know the parties involved.
