Shape of the QF PE seat does not suit me. Bits of the seat dig into various parts of my body in PE somehow (and it is quite painful!), whereas QF economy seat doesn't.

I'm as narrow as a healthy adult can be, so the seat width is not an issue.

I don't recline fully even when sleeping in long haul economy (except in the event of having no-one behind me, which is rare - then I recline further because I have no-one to be considerate towards), so the further recline provided in PE does not benefit me a lot, either.

So, overall, economy class exit row is a much better option for me than PE.