Okay, the board arrived yesterday. So far both VMWare's ESX 3.5 and 3.5i are able to boot, install, and stay stable.
I'm not using the LSI SAS controller as of yet - Just the Intel Matrix controller, with a plain old SATA drive. I haven't created any RAID, so both versions of 3.5 are able to spot the Intel controller and work just fine.
This means that people wanting to save a few bucks could use the Intel 6321 controller only board (no SAS).
Watch out - Make sure you use SATA ports 1-4. Ports 5 and 6 are not spotted by the install scripts.