RHEL 6.2 RAID 0 & 1 Vs RAID 6

RAID 1+0 is something that is easy to create under HP using Smart Array Controller. Is there any overwhelmingly good reason to use RHEL's capability to create RAID 5 or RAID 6? Other than more space, we figure 3 TB is quite a bit.

Anyone have experience building their own ArcSight ESM 6.0c CORR Manager using RHEL 6.2? Experiences? suggestions?

Thanks, David H.