[Chris Trahey]

With the same number of drives, the breakdown is like this:
RAID 5: Much better read performance, theoretically MUCH slower writes.
RAID 10: balanced read/write, with the read performance roughly equivalent to the RAID 5 with half the number of drives -1.

Take my latest two servers for example:
One has a set of 6 drives, and I needed balanced read/write, so I choose RAID 10 (which is essentially a 3-drive stripe in terms of performance).
The other has only four drives, but I do not need write performance, so I choose RAID 5, which give the same read performance on these 4 drives as a RAID 10 on 6 (3 drives striped).

So it depends on what you are using the server for. If you are only streaming off of it, choose RAID 5, you’ll have BETTER READ speeds with the same number of drives, AND increased capacity.
If you need to write to it (Render Cache), RAID 5 will in theory be slower. Of course a great card goes a long way.
If you care a shred for performance, don’t use RAID 5 software.