Received a few days ago my K10C. The first thing I noticed is that the new logo (see my
old post) looks FAR better IRL than it does in the photos. Seeing it only in pictures I was concerned that the new metallic logo is not as impressive as the old one, but now I'm really happy with the metallic logo, it surely looks very cool and classy. Also, thank you, John, for complying with my request of doing the Mystic Swirl in a blue color. It looks gorgeous and while it's clearly a matter of personal preferences, I find it more fascinating than the purple one.
Regarding the sound, I'm surprised that no one calling the K10 a "bass monsters", because for me they definitely seem to be the ones! I'm not a basshead for sure, but for one thing I like my Fostex TH900 that are clearly a bit heavy on the bass side, but the K10 simply redefined for me what a "bass heavy" is. Never believed that an IEM could produce these levels of low frequencies, it feels like a mini subwoofers implanted into ears. I suppose that this experience relates only to custom K10's as they go deeper and seal better than the universal ones, amplifying the LQ perception, also soft universal tips should absorb LQ a bit more than hard acrylic. Anyway, I started using EQ to roll off LQ a bit. Probably it won't be needed anymore with an appropriate aftermarket cable. Still, while K10's LQ quantity is a bit excessive to my ears, its quality is simply stunning and the control is amazing. As for the mids, vocal range is slightly forwarded, that's a good thing for me, and regarding the HF, I find both the amount and the extension just at the right levels. I don't hear any loss of HF information even on most complex classical pieces, while the sound is still comfy and forgiving enough to listen to J-pop like Aoi Eir for example, that I find too bright to my ears on the most headphones. Though I can understand that some people prefer more airy and open presentation (like SR-009 or HD800), I enjoy SR-007's sound more and the the K10 seems definitely close to SR-007 to me.
Prior to the K10 I never heard an IEM with a soundstage I could rate as any decent. While I know, that some people say that the K10's soundstage is only mediocre compared with some other TOTL CIEMs these days, for me the K10's soundstage is like a revelation, since it's the first time I hear some real out-of-head presentation coming from an IEM. That's more than enough for me and much more than I expected anyway.
To summarize, I think that going with the K10 as my first CIEM was a very good decision (FYI: the Katana wasn't announced yet at that time).