That has nothing to do with the files system that is due harddrive manufacturers using bytes instead of bits for measuring the capacity (1 byte = 8 bits). Your hardrive is advertised as 60Gb but is actually 60000000000 bytes or 55.87935447692871 GB.
Edit: beaten!
I'm using it right now and it's very nice, but does have it's issues. Once it's released on Linux and has been through a few more updates I'm sure it will be worth consideration.
Looks nice enough, could do with something like that on Pandora. I tried the windows version and it was using near enough 200mb of ram doing nothing so I would hope the linux/portable version was much more efficient.