Adaptec/LSI/?? RAID

We're in the process of buying another Opteron server to run Postgres, and
based on the suggestions in this list I've asked our IT director to get an
LSI MegaRaid controller rather than one of the Adaptecs.

But when we tried to place our order, our vendor (Penguin Computing) advised
us:

"we find LSI does not work well with 4GB of RAM. Our engineering find that
LSI card could cause system crashes. One of our customer ... has found that
Adaptec cards works well on PostGres SQL -- they're using it as a preforce
server with xfs and post-gress."

Any comments?  Suggestions for other RAID controllers?