the trend lately is two fold:
1. boot usb or boot off cheap SLC samsung older drives.
Sata Intel rstE is the fastest for sata ssd
then lsi or the 71605e
then the megaraid/p420/adaptec 71605 (standard raid).
SAS to SATA overhead costs you too much, so if you want SAS , buy SAS ssd !
Waste all that money on expensive megaraid or P420 - then you bypass the controller back to dumb mode (LSI FASTPATH, HP SMARTPATH[new!]) and well you might as well have stuck to the simple faster.
HP can boot eRST, LSI 2308 IT both with the HP VSA driver (esxi too!).
Fastpath is basically cut through switching - LSI and HP both have said it is designed mostly for several drives in raid-0 (ask them!).
Why pay more for less performance? silly.