Ion vs PMR
Olly,
Straight out of the box the PMR is better than the Ion, as is reflected by the price. The PMR is about £230 and the Ion £130. I've heard a few stories about the PMR bolt being a bit poo, but maybe others who have had first hand experience could help you with that.
I'm a big Ion fan, well at least a big fan of my Ion, which I've upp'd and upp'd to the point where it out performs all other entry level and most mid level markers, but if I was to buy again from scratch with a limited budget I would probably get a PMR. Mate uses one and he is very pleased with it. Nice bit of kit.
Hope helpful.
Cus.