I love them. I posted some initial thoughts earlier, but here are some observations vs the A18s which I know you own. To be honest, after taking part of the tour you organize for the U18s, I can't forget them. I fell in love with them and to date they are the best I've heard. The A12s don't wow you at first listen like the U18s, but after a few minutes you realize how special these are. If you like a warmer smoother, but well extended and non fatiguing sound, these are the ones. They can hit hard, at basshead levels with the M20s and are more balanced with the M15 modules. The U18s are more revealing, a little more forward in the mids from memory and brighter on the top end. The A12s on the other hand are smoother with very nicely extended high end that doesn't fatigue. I could listen to thees for hours with no fatigue, yet for my personal taste, I don't find that I am missing anything. In fact, after switching to brighter iems, they sound more artificial vs the !2s which are very organic. In a perfect world, I would own the U18s for personal listening at home, etc and the A12s for playing live music.