No first hand experience JonB, but from reading their web page, it appears to be usable on Linux systems only (or primarily) right now.
FreeBSD support is now stable. Look for NetBSD, OpenBSD and OSX support in 2
If you wanted to use it to check out a host's configuration, I think you'd need to be a customer FIRST, then upload and run the script. Also, the web page says it's written for system administrators. As a hosted customer, it's likely that you wouldn't have adequate permissions to access some of the info the script provides.