Sure, streaming to/from RAID0 will always kick ass. However, who really runs RAID0 these days??? (I'm sure there's about <.1% of applications where RAID0 is suitable, because the data is not critical) RAID 0+1 might be a slightly better comparison since the filer doesn't
have
a RAID0 mode.
Of course, with RAID 0+1, you're paying for twice as many disks. For the same money, you could buy a second filer, and spread the load, and get better performance for the same dollars. (And a better MTBF).
Bruce