rsync.net is run entirely on FreeBSD. Further, it may interest you to know that we (JohnCompanies) used FreeBSD and jail to provide the first VPS services[1],

rsync.net is run entirely on FreeBSD. Further, it may interest you to know that we (JohnCompanies) used FreeBSD and jail to provide the first VPS services[1], back in fall of 2001. The VPS as we know it (which appears to be dying in the world of EC2-style instances) came into existence as a direct result of jail. [1] Yes, Verio did have that bizarro VPS-like service that cost an arm and a leg a year or so earlier, but the VPS as you think of it was first provided (AFAIK) by JohnCompanies in 2001.