[CentOS] CentOS on Compaq Proliant Rackmount Servers

Greetings,

Can anyone relate experience(s) installing CentOS on Compaq rack mount
servers units please?

Easy no problem, easy some issues, or ghastly do not do it under any
circumstances... ;)

Basically, I'm looking at some used/refurb dual PIII units and will run RAID
on Compaq built in SCSI or is it easy to pop in some 3ware SATA in them?

Let me know in terms of CentOS 3 and/or 4 please.

Regards and TIA,

 - rh