I haven't checked recently but nVidia also used to provide decent support for FreeBSD and Solaris.
There was a stink a while back where Adaptec had been providing drivers for FreeBSD, but then stopped. People were stuck either not upgrading their boxes (bad!) or moving off their RAID setup (painful, expensive!). It's ugly. With specs, there is not this issue.
The (pervasive) idea that vendors providing drivers for your system of choice, for the time being is being open source friendly is something the vendor promotes, but it's not actually friendly.