I've lived with these headphones for a few weeks now. Firstly, the audio quality is exceptional. It's like having some nice Genelec monitors stuck into your ears. These IEMs are levels above my previous ones which were Shure SE315 and SE425. Of course there is a big price difference, but you can certainly hear where the extra money has gone. There is so much more detail in all frequencies and overall the sound is balanced and a real joy to use. Listening at lower volume is also a great experience, the outside world seems far away if you get a good fit with the earpieces. You can still hear and enjoy lower volume music in great detail and classical music allows you to pick out the various instruments extremely well. There is also bass available, you just have to balance it from your sound source to get it exactly how you like it. Even before balancing, the bass is accurate, but you may want a very slight boost if that's how you like your music.
A couple of points to note are the fit. The supplied softflex earpieces aren't big enough for my ears. They are supplied in Small, Medium and Large but the large are loose in my ears. So I had to buy some extra Shure Ultrasoft flex sleeves also in Large - but the Shure Large is bigger than the Hörluchs Large bizarely. It's a real shame because the Hörluchs flex sleeves look like slightly higher quality than the Shure, but it's no good when they just don't fit. I tried the foam ear pieces and they fit me and provide fairly good sound isolation, but I just prefer the soft flex dome ones and they seem more durable than the foam version.
The other point to note is that the wire is much thinner than the wire on my Shure IEMs. I've had no problems with it so far, but I'm concerned about the long term durability. It has a slightly thicker reinforced tube for the wire that goes around the ear, but it's not mouldable like the Shure so you can really bend it around your ear and it stays rigid. It does conform to your ear because it's floppy, but I would have preferred the stronger Shure kind. I've gone through one replacement Shure cable maybe every couple of years because I'm using the IEMs for possibly a 2-3 hours a day so quite a heavy user. I'm not 100% confident that the Hörluchs cable will be this durable and the replacement cable is quite a bit more than the Shure replacement cable. I guess time will tell and it may not be an issue at all.