Comparing Dell PERC 6/i SAS RAID Against HP P800

Does anyone here have direct experience using the HP P800 SAS RAID
controller against the Dell PERC 6/i under Windows 7 64 bit? Which is the
better controller? What matters to me, in order:

1) Least likely to fail (I have had HP hardware RAID controllers
spontaneously lose their entire configurations on rare occasions, typically
when there is a significant disk failure and during the rebuild)

2) Most power feature set under GUI software control (i.e., I don't want to
get into BIOS software to do essential functions)

3) Easiest to use GUI user interface