there is no issues running exchange 2010 on sata disks as you just pointed out Microsoft built exchange 2010 for JABOD (Just A Bunch Of Disk)
From Exchange 2003 to Exchange 2007 we have an I/O reduction of 70% and another 70% from 2007 to 2010.
I have been running Exchange 2010 on sata based SANs without any performance issues