Just reporting that I started playing with it - and more than playing. So far so good. The architecture is really simplistic, the executables very lightweight. For more detail see here:
I am running it on several server-class boxes using VirtualBox VM's to emulate a network so as to be able to distribute it to multiple hardware boxes later on. Both the VirtualBox hosts and the VM's are running CentOS 6.
The only problems so far seem to have to do with integrating MooseFS with other technologies. I tried using the UNFS3 user-space NFS server to create an NFS gateway to the MooseFS installation. And so far it looks like the UNFS3 server does not scale well to multiple connections. In other words, you get an excellent performance with one NFS client, you get a decent quality with 2-3 connections but when it is above 5 it seems to go down the drain and accessing one's home directory over such an NFS connection becomes pretty much unfeasible. So at this point what's lacking is a good NFS gateway for situations where a MooseFS client is for some reason not available or not a workable solution. Or perhaps I will choose a different sharing method. Time will tell.