i've used m160's and m130's in the studio a lot. the engineer i interned for used them on a lot of instruments. drum overheads, percussion, violin, a pair on leslies, and even on some electric guitar amps.
i think they a have a very smooth and natural sound and i wouldn't mind hearing more concert recordings made with them. i bet they could sound real nice. the only drawback is that the frequency response really drops off after 16k. HF adjustments in posts might be necessary for a lot of our applications. i know i had to bump up the highs on a lot of instruments in the studio to get a nice overall sound.
i know that probably doesn't really help to much for our purposes, but i thought i'd offer my experiences anyway.