The sound samples I made a link to are made with B&K 4145 not the Microtech 296. I do not think the 296 will have that "silky" sound in the top end.
To choose between 296 or 102/4145 depends on if you look for the round sound as heard in my example, and if you like the sound of microphones like the SCHOEPS mk2.
The decision between Gefell 102 or B&K 4145 depends very much on what you want to spend on them. The 4145 are discontinued, but probably still on stock, but cost about the double of the Gefells.
About the quality, my friend Kostas Metaxos used many equivalent capsules from B&K and Gefell, and always preferred the B&K's in terms of sound quality, but this is very personal.
To go back to the 296, this microphone is a modified 102, works with a lower polarization voltage, not to accomodate a special sound, but just for the easiness of the fact this preamplifier is used for more existing Gefell microphones and runs on 48V.
The effect of the lower polarization voltage is the presence peak, and indeed it gets a bit the characteristic of a microphone placed in a sphere like the Neumann M50, but the fact the shape of the 296 is not spherical, it will never sound like a M50.
I use the standard Falcon preamps from B&K to match it with my Lake-People V25 preamps, using a mechanical adaptor.
Hope this helps,
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