you can setup blinkies in Olympus (or zebra in Sony) cameras to give a real time indication of clipping in raw in your EVF - but that's one more reason to use UniWB btw (unless you do not mind spot metering) as it will be more precise than w/o it...
I never use any kind of metering on this camera, it would be silly since the EVF provides easier handling, higher accuracy and much more fun.
I want to keep the JPEG files correct because Olympus colour engine is great, so UniWB is not an option.
Finally thanks to its low effective ISO, highlights tend to be sotfly desaturared towards white and clipping is very progressive in Olympus, making its JPEG files very usable.
In brief: I seldom miss ETTR, UniWB or RAW shooting with the E-P5, even if I have been a heavy user of them all in the past with Canon.
Regards