So I've had the Havi B3 for a while now. My review is that it's the last power hungry, hard to drive IEM I'll ever buy. Great sounding IEM, if you can drive it. Not even my FiiO E10K is enough, unless I also use the E11 along with it. Properly driven they have absolutely beautiful sound, but then my brain clicks on, and finds it silly that I'm dedicating so much juice to a freaking IEM.
The SQ is very impressive, but I find myself annoyed that my phone and laptop can't even get it to what I'd consider "almost loud", and since I'm using IEMs outside of the house more and more often, the idea of bringing an amp along just doesn't fly with me.
So don't buy them unless you're really about dat life. They just don't mesh with my lifestyle. They don't really even beat the much easier to drive Ostry KC06, which I reach for every day, in any area other than soundstage.
tl:dr - buy a KC06, (or KC06A if you want more bass)
I actually have a KC06A arriving tomorrow, for comparison's sake