While I do agree with the use

While I do agree with the use of hardware RAID, most home users do not need RAID 1+0 (aka RAID 10 but less accurate).  The times where RAID 1+0 shine is if you need a high performance writes.  For a business, even small business, RAID 1+0 is a given for servers.  For home HTPC usage and media storage that typically is not a concern and if it (write performance) is then I would suggest a different setup entirely then.

Note: While RAID 1+0 is typically the fastest overall RAID level (RAID 0 is faster but not redundant so it is arguably not a RAID level and wasn’t one of the original RAID levels) with 4 disks RAID 5 arrays can perform better than RAID 1 + 0 so if you are only looking at a 4 disk array the performance benefits can be moot.

My SAN is setup for RAID 1+0 and my media storage is RAID 6.  For NAS media storage I recommend RAID 6 over RAID 5.  In addition to being able to lose an additional disk, RAID 6 has a higher level of protection against block failures and controller errors by the extra parity over RAID 5.  RAID 6 has a lower impactful on disks when rebuilding. 

If you do build a DYI NAS I strongly recommend a discrete RAID hardware controller with a Battery Backup Unit (BBUs) in addition to a UPS.  I tend to go with 3wareLSI.  Not having a BBU will kill performance and put you at a higher risk of data loss.

BTW, In terms of Magic ISO please see http://aluigi.altervista.org/misc/magiciso_gpl_violation.txt.  I highly recommend using ImgBurn + Virtual CloneDrive instead.