Juliet Kemp from serverwatch.com has tried, used and reviewed FreeBSD 8.1. Though she had some issues with installing the operating system, she agrees that if you want stability and control over your system, FreeBSD is definitely to be considered:

FreeBSD is definitely not as user friendly as modern Linuxes — you’ll need to be a lot more familiar with what’s going on under the hood and perhaps more prepared to have a couple of goes at the installation. The packaging system works well, however, and the number of available packages is comparable with, for example, Debian.

If you want close control over your system and the software you install, FreeBSD is a decent choice. But be aware that if you’re a current Linux user, you’ll have a bit of a learning curve in front of you. This is not to say either style is better or worse, just different, and adjusting to differences takes time. Having said that, I got a working desktop system and a couple of server applications up and running within a few hours, and a lot of that was download time. It’s a powerful and functional member of the UNIX-like family, and reviewing it has certainly interested me enough to keep on experimenting with it. If she’d installed FreeBSD with the PC-BSD installer (pc-sysinstall) things would have been easier ;-)

Full review here: Getting Started with FreeBSD 8.1