I thought I would post some more impressions after a few more hours of listening.
Overall build: The cable is pretty thick from the Y-splitter down, which I like. I also like the 45 degree 3.5mm jack, which will stay put even if you yank the cable pretty hard. The rest of the cable seems to be of high quality as well. The housing, although entirely made of very light plastic, seems pretty strong. My PL50 is from the second batch, so I'm keeping my fingers crossed that the housing won't split, but future buyers shouldn't have this problem. I can't comment on build quality too much yet. I will just have to see if they last.
Sound: Soundwise, I'm still learning to adapt to their sound signature. It's a bit light on bass and I find EQ'ing to be unavoidable. I especially dislike that everything below 60Hz (going from the Rockbox Custom EQ) doesn't really improve that much, even when you go all the way up to +24dB. Maybe my seal is the problem, or these just need some more burn-in, but this is the biggest downside for me. The rest of the spectrum is beautiful however. The biggest difference you will hear coming from stock earbuds or IEM's are the crisp highs. They don't sound harsh at all and really give some extra feeling to for instance rock music. Mids are great as well, vocals are quite forward and guitars sound really nice. I'm going to have to give these some more time to make my final conclusion.
Would I recommend them for now? Yes, as long as you're not a basshead and you aren't afraid of Chinese products. Just one word of warning: don't try to take the foam tips off with pressure if they won't budge at first. You will most definitely destroy them completely.
It's a bit short right now, but if anyone has any questions, feel free to ask me. Oh, and tips concerning EQ'ing or something else would be appreciated.