X-bit Labs has compared five RAID controllers from Adaptec:
What do people do when they run short of the performance, capacity or reliability of even the best hard disk drive? They turn to RAID technology. People who need increased reliability go for RAID1. Users who have lower speed and reliability requirements but demand high storage capacity and low cost of storage prefer RAID5 or RAID6 (the latter is a variant of RAID5 but with two checksums per each stripe). RAID0 is for speed. Both speed and reliability can be ensured by using RAID10 or, less frequently, RAID50 and RAID60, which are two-layered combinations of the basic arrays. It is all quite simple and you can easily select a suitable RAID type for any application, from workstations and entry-level servers to high-performance servers with lots of HDDs inside..