3com 3c996b-t support?

Is 3c996b-t gigabit ethernet NIC supported with the
tigon3 driver?  The driver in the kernel lacks documentation
as too what it supports, at least I couldn't find any.

On another note, 3com provides GPL drivers for this card,
is there a reason why these cannot be merged into the kernel?
Or is it basically what the tigon3 is?  Has anyone tried these
drivers out and found out which performs better?  Should I
stick with what 3com provides or go with what is in the kernel
if it works?

Thanks,
Steve