Some gotchas:
3ware RAID 5 sucks and especially when in degraded mode (and this goes for a lot of other hardware RAID cards) because the onboard processor is not fast enough to handle the calculations. Hint: If you see an Intel 960 processor on your RAID board, forget RAID 5.
Forgot to tell you that this is when you have a fair amount of writes. For example, as a fileserver that sees a lot of changes/additions it will not be as fast as a Linux RAID 5 setup.
Linux RAID 5 will be much faster so forget the 3ware RAID card if you want to do RAID 5.
Primarily because any CPU you get today is going to be much better than an Intel 960.
