They all suffer from the good enough but not mainstream enough problem, i.e. official Nvidia drivers that are not officially supported.
It made for an amazing mailserver last I tried it though. I used 3.4 on an ancient P4 with maybe 256MB of RAM an 8GB hard drive. Turns out that was way more computer than it needs, and it was so stable I began to think of it the same way I think of my router.
To hell w/ NVidia. If they won't play ball, I'll spend my money on an arguably slightly lesser performing product that is more open.
Though, currently the linux emulation layer in CURRENT has a change that broke the linux Flash binary. I've been flash-free for about 2 weeks now. I can't decide if that's a curse or liberation. Otherwise, I personally think FreeBSD is a mighty fine desktop OS. ZFS is really nice.
And I don't think the users of other BSDs have much need for 3D acceleration..