I could have bought either, APP had just been released when I was looking to purchase. I went for PBP because I needed something to use only for training. I run, marathons, and that was my only criteria. Cleary for training PBPs are a better form factor with the over ear design. For me sound quality was never an issue. when your 25km in, SQ is not really something you think about, loose fit and having to constantly poke your ear is. I have Audeze iSine 10 and LCD2, plus ATC active floorstanders for my home system, so I’m kind of covered if I want to do some critical listening, and Apple are going to have to go a long way to come anywhere near the SQ of my serious kit.
So far happy with the PBP. I cant feel I’m wearing anything once I get going, and that’s with running glasses too, so don’t believe reviews that suggest using glasses with them will be uncomfortable Occasionally need a little poke to seat them a bit more firmly. But very comfortable in general.
oh, just remembered....negative - no good for cold weather if you need to wear a beanie or ear warmers, they’re too chunky. I am considering some APPs for this.....dunno I’d I want to spend this much money though.