The tradeoffs are severe and at this point it is not interesting enough to risk a project.
- EOX is providing the real guest OS even though it's not a complete or real OS
- The filesystem is only a fraction of traditional services
- I'm not sure whether or not filesystem snapshotting is possible
- You're stuck with erlang
- they are even using BEAM files
- there is still a host OS
- it's not open source yet
- it's a commercial project first and foremost
you should checkout docker.io first. At least you'll have more choices before getting locked in.