My review of the BA4 is up
HERE, which covers many other custom IEMs as well. I'm not sure it came out quite as clear as I wanted in terms of my feelings for the BA4 - there's a word count limit, and I likely went over my allotted amount anyway.
So to clarify - the BA4 (along with the UM Merlin) didn't receive our general "Stuff We Like" recommendations. Not because I dislike the Merlin or BA4, but rather because they are somewhat more specific in their application. Neither is really a general use type of IEM where you could be safe recommending it to most people for most music. To be fair though, for people who like their respective sound signatures, the Merlin and especially the BA4 are actually
better than some of the more universal recommendations. In fact for some people the BA4 might be
the choice of that whole collection. And don't forget it costs roughly half compared to most others.
I do really enjoy classical on the BA4. Been listening to a lot of solo piano stuff, and Yo Yo Ma, and Vivaldi, etc and the BA4 is super impressive when used with a good source/amp. My Sansa Fuze just makes it seem
meh but the iHiFi960 brings it to a whole other level.
I don't want anyone to walk away from that InnerFidelity article thinking the BA4 is not a worthy choice. It absolutely is, as long as the context is considered. I imagine the upcoming BA5 or BA6 would have been more competitive in terms of being similar in character to some of the others.