getting your root fs over a wide-area network can be quite painful; you're not moving a ton of data, but the process is very latency-sensitive. i've not done it in a few years, but boot times of 5-10 minutes were not unusual. cfs(4) cut it to about a quarter that.
still, what i ended up doing was booting locally with a termrc that connected to my file server and pulled in what i wanted. it was a bit extra effort to maintain, but the time difference was more than dramatic enough to make it worth it.
