So I have the new Pola39 on hand. Although this is just a beta, but I'm told it's pretty much the same as the final tuning. Just not the final build.
First off, I did audition the original Pola, but I can only explain from memory : I didn't really like the original Pola. Crin's impression is pretty spot on... When I tried with the ZX300. Trying with other DAP like Fiio M6 and M9, it sounded much better. Heck even from my iTouch was much better for some reason. The bass was not as muddied. Instrument separation was much better and the decay improved. Soundstage was above average but accurate. Tbh, I was kinda disappointed.
Then there's the Pola39. I like this sooo much better than the original. The darker sounding of the original pola is now much brighter, but not as bright. Bass is tighter now. Mids are almost the same I think. The highs are a notch better. It's just overall so much better. Worthy of being called flagship alright. Tried a cheap silver plated balanced cable with my Q1mk2 and the decay actually became even faster. It actually felt "too quick" for my liking. The rest of the frequency didn't suffer much though, if any at all. Overall, this is a very very good iem.
While insufficient, this is the limit of my audiophool explanation capability goes despite being in this hobby for years. If there's any questions, I'm more than happy to try and answer as best as I can regarding the new Pola39.