I agree that encoding is CPU dependant and that disk I/O is less important. Which leads to the following...
I have read a lot of posts on numerous forums, and the general concensus is that it is not good to use Raid for dvd decoding or encoding.
Is it important, or isn't it? FWIW, I have first hand experience that RAID is indifferent in the encoding/decoding process.
There are a very few people who have had good results with it, but not many.
Can't speak for the many, can only speculate that improper setup or hardware fault was the culprit. My experience is exactly the opposite, those who have chosen to go the RAID route having problems is the exception, not the rule.
Some people have even had problems using Sata, but there aren't many. The number 1, most fool proof decoding/encoding solution, is a dedicated IDE HD, followed by using a dedicated SATA drive.
This requires your definition of 'fool proof'. If you mean 'easiest to configure', I would suggest that SATA is, as it requires no jumpers to configure or cable concerns. I will agree that RAID does require some investment of time to overcome it's learning curve. Not much of one IMO, but that will vary with the individual.
I'm sure that some people will disagree with me, but like I said, I'm just going off results I have seen in numerous forums on this subject. I personally use dedicated SATA drives on both of my systems, and have had excellent results.
Again, my first hand experience differs from what you've read. I think it's great that your setup is giving you excellent results. My setup also gives me excellent results.
I have read many of your posts and have been in agreement with you on many things. It is not my intent to get into a flame war on this issue, I'm only offering another perspective to consider.