I guess the weekend came early for me.
Couldn't wait so pulled the trigger on the ICS update.
Experienced some initial lagginess after turning on the device but now, it appears to be running pretty smoothly.
Ran Passmark and results for 2D and 3D graphic tests were lower compared to Gingerbread. Perhaps due to ICS using some GPU cycles for UI hardware acceleration? Anyway, if you game on your Ray, it might not be a good idea to update. I've only used ICS on a tablet before so didn't know exactly what changes to expect on the smartphone. Happily, the ICS interface is a lot more intuitive and certainly feels more polished than Gingerbread. All in all, I'm pretty happy with the update.