I normally don't use the ICH for raid and I've never used WBC for anything but testing. (on the ICH that is)
IRST 9.6 looks like a better performer using wbc so I might end up keeping it on for everyday use. (until I get a new raid controller at least)

Previously, using wbc performance dropped in some areas but 9.6 is almost identical using low stripe sizes whether wbc is on or off.
The exception is of course 4KB writes at low QD which gains a lot using wbc.

Here's CDM at 4KB stripe size

wbc off to the left, On to the right.
cdm3_4kb_ss_wbcOff.PNG cdm3_4kb_ss_wbcON.PNG