Alright, quick impressions time after 1 day listening time:
Fit:
Quite difficult to get a good, deep seal, but I managed to figure it out. I use the smaller comply tips and put them in deep and then rotate a bit to get a good fit. Also requires some readjustment from time to time, so they are not easy to put in quickly.
Sound:
I'm really digging the sound signature on these, everything is in its right place. Nice and flat throughout the frequency range, but not a boring neutral sound at all. Overall very lively and energetic.
Nice treble sparkle and extension, but not too much and absolutely no sibilance, unless it's a **** recording. Mids are amazing. Lower and upper are so well balanced that nothing gets too hot and you're not missing any type of vocals, male or female. Bass is nice and flat, mid-bass hits pretty decent, but no slam, although I did do the front vent tape mod. It's true that the end of the sub-bass is rolled off, but it's not missing much. If the recording has lots of sub-bass you will hear it and if it does not you will get the right amount.
On soundstage and separation, they are definitely sub-par. Nowhere near the level of a multi-BA or hybrid setup in this regard. Speed is ridiculous and is the real selling point, along with the fantastic sound signature (for my preferences).
Power:
This is where things get interesting. You need lots of power and current to drive these. Like it's no joke, these things are real thirsty. Initially, I was listening in balanced mode on my Opus #1s (high gain) with an output of ~360mW into 32ohms or 3.4Vrms no load. That was not enough power and I had to get near the end of the volume pot, which I've only had to do with my ATH-R70x (470ohm).
I then pulled out an older single ended amp with an output of ~700 mW into 32ohms and was finally able to get enough power and headroom to listen comfortably. Only with this much power was I able to get the full sound of the P1. Sources with not enough power make them sound quite poor. I'd recommend you have a source with a power output of at least 500mW into 32ohms.
Value:
For me these are a no-brainer at $150 for which I got them. Hits a lot of points I look for in the sound signature, speed, comfort, etc. Portability may be limited due to ridiculous power requirement, but I will be happy to use these as my daily drivers. I'm not trying to get into any chifi debates here, but honestly if I had spent $300 on these I would be just as satisfied.