I just got mine in the mail today, and I've been listening to them for about an hour (typing this up as I'm still listening). First of all, thanks to Baycode and various other contributors on this thread for recommending the Havi-B3. As far as initial impressions go, I'm super pleased with the packaging/presentation as well as the all extra goodies that Penonaudio packed with it. I've never seen packaging as fancy as this besides the now-discontinued RE-262. Now before I get into initial impressions of the sound, I should first make a disclaimer: yes yes, it's only been an hour or two, so this "review" should be taken with a grain of salt. I am aware that the Havi's sonic characteristics will change over time. Also, since this is my first in-depth review of some sort, please go easy on me. I will only give generalizations and not do any A-B comparisons anytime soon until these burn in, or at least until my brain adjusts to the transition. My audio chain for this is Foobar2000 -> O2 amp -> Havi, and the IEMs I usually use are the TDK IE800 (at home) and the RE-400 (on-the-go).
The first thing I noticed when I plugged these into my ears is how darned hard it was to get a good fit. It was about 15 minutes later after tip-rolling did I realize that the default tips that Havi put on the B3 was the large ones and not their medium ones (I thought most IEMs have their default tips as medium). After settling with the red-black medium tips, the second thing I noticed was the amount of sub-bass that was hitting me. The sub-bass is plenty and satisfying, but the amount of mid-bass is too much (I even think the RE-400 has a bit too much bass), that for a moment, I thought I ordered the Pro-II by accident. I know Baycode said that the bass settles down after burn-in, so we'll see about that - I'm not going to make any senseless speculations.
The mids are less warm than the RE-400, which I believe made mids on the Havi sound more "clear" in a sense. The treble didn't particularly stand out at the time of this write-up, but it did have a slight sense of airyness and slight sparkle that I've been searching for since my RE-ZERO died about two years ago. The other IEMs I've been trying around the $60-$100 range either have slightly hot and/or metallic treble (XBA-3, TDK IE800, HSA BA100), or was a bit too smooth for my taste (RE-400). As far as efficiency goes, I don't think these are any less efficient than my RE-400, since I used the same settings for both and got comparable volumes. Maybe the sound details of the Havi don't show up as easily without an amp, who knows?
Concerning the soundstage, I'm going to repeat what many others have said. The soundstage is this IEM's forte, and everything sounds so... coherent (for a lack of better word). I have a feeling that the RE-400's mid/vocals would beat out the B3's if only the soundstage on the RE-400 were bigger. From memory (big disclaimer), the B3's mids aren't ridiculously so much better than the other IEMs' mids that I've tried, but the soundstage is what makes things work. Without it, it would probably end up sounding like the RE-400 with more bass and more airy treble. And of course, there's the obligatory "OMG I heard new things in my music that I didn't before." No, I didn't hear new instruments or whatever, I just heard a couple of new notes here and there that I struggled to make out with the previous IEMs. Again, it could be due to the soundstage and the separation that makes each individual instrument easy to track. One slight "disappointment" that I had was that the soundstage width wasn't as amazing as the RE-262's width. When I used the RE-262, there were occasions where I literally turned my head because I thought someone was talking to me (the people on the subway looked at me funny). Based on the compliments on this thread, I thought I would have a similar effect, but hey, this is only a fraction of RE-262's $100 price tag.
Value-wise, I think these are amazing for $59 (WOAH, not even $60). The clam shell case they included is so polished that it beats a lot of hard cases included with other IEMs (Etymotic, Brainwavz, ME-Electronics, HifiMAN, etc.) The pouch case is a nice bonus, but I don't think I'll ever use it. But wait, there's more!!! They even included a microfiber cloth for wiping... the glossy surface on the B3? Normally I'd just use a wet towel to wipe the earpiece and the wires, but it's nice that they included a microfiber cloth. Anyone with an amp should give this a try (I haven't tried it without an amp - I'll do it tomorrow when I head out). For $59 I am not disappointed at all sans the soundstage width compared to the RE-262's =P.