For the higher-end of things, 3Ware and Areca have the best Unix support in general, and FreeBSD support specifically. Both employee developers who do nothing but FreeBSD support. They offer updated drivers on their website, and the drivers are also shipped as part of FreeBSD.
Depending on which reviews you read, 3Ware is faster than Areca, and Areca is faster than 3Ware.
I've only used 3Ware controllers, as the Areca were too expensive when we started out. The 3Ware controllers have very nice, easy-to-use BIOS config tools, as well as a web-based management tool (3dm2, in the ports tree).
I have no experience with middle-of-the-road RAID controllers (like Highpoint, Promise, Adaptec, etc) so can't comment on those.
We used LSI MegaRAID SATA RAID controllers a couple years ago, and they left a *very* bad impression on us. We returned a whole bunch, and just scrapped the ones we couldn't return.