Wait, wait ... you find ... VSS' usability to be better than that of Subversion?
Do you know of any other people with this affliction?
Which Subversion *client* did you try? Telepathy 0.6a?
In any case you lost me with that. Your ideas of usability must be on a different planet. Maybe that's lucky for you; ours is overpopulated.
Over here, Subversion and Trac were *dead easy* to set up and integrate, including scheduled backups (took literally minutes) and migration with history from VSS (took a bit longer, but have you tried the same from VSS to TFS?). And they performed just fine --- on a VMware virtual machine with SAN disks.
We have TFS on serious hardware, serving no more than 40-50 users with a repository of 4,7 GB. My Visual Studio takes 38 seconds --- blocking the entire UI --- to rename a file. That's even at night when I'm alone in the office. 38 seconds means kiss your flow goodbye.
It shouldn't take that long. Even on mine, which is running on a VPC with maybe 512 of RAM, it took under 10 seconds.
I'd put a sniffer on to see where the bottleneck is coming from. Maybe grab some Perfmon data from your server - maybe you are running into hotspots on your SAN or something similar.
Feel free to contact me offline at foyc at cornet design dot com and I'll be happy to work with you to see if we can track down the slowness.
Although I agree with your SVN comments - I really enjoyed working with it on the projects we used it for. I especially enjoyed how easy it was to add pre and post hooks to the check-in process.