I am no expert on this but our company has a x3650 M4 and the extras I have seen is the support for the hardware, RAID card & sensors. From in vSphere you can see all the sensors and get the warnings/faults etc. You also get full control via IMM2 if you use that management interface.
I tried the ESXi 5.1u1 before IBM got around to publishing their own and it worked but any specific items for the hardware was unknown.
Dhusby