[CentOS] C5 64-bit and software RAID 6?

I have a Dell PowerEdge 2950 with 6 SAS disks and a PERC 5/i controller 
what won't do RAID 6.  I plan to have 2 drives as RAID 1 for the OS, and 
the remaining 4 as RAID 6.  Granted the PERC can do RAID 1, I'm tempted to 
do everything via software RAID.  Thus, if anything goes wrong with the 
controller, I just need to obtain a new SAS controller and I'm back up.

I learned my lesson about not using RAID 0 for important data storage when 
a drive goes bad!

What are peoples' performance and reliability experiences with 64-bit C5's 
software RAID, particularly RAID 6?

Thanks.

Scott