I've been amazed at the versatility of this mic. I've tried it on guitar, violin, viola, cello, accordion (right hand), concertina, hammer dulcimer, and even as drum overheads. I have seen them being used to great effect on highland pipes with Peatbog Faeries at Sidmouth Folk Festival. I believe it to be a fantastic all round mic for close micing live or in the studio. It has good rear rejection and it doesn't feed back unexpectedly.
On violins and violas, so many other pickups and mics overdo the treble response, leaving the violin sounding harsh and cheap. This one has a much warmer tone and reproduces the violin's natural sound very well if the mic is placed directly above the bridge. I have found the best location for the clip is the lower left corner of the body. The best position for guitar was also as close to the bridge as possible.
The violin clip and guitar clip are able to be attached to practically anything they will fit around and, with a good squeeze, don't fall off even when playing vigorously. The rubber holder that supports the mic means that knocks on the bodywork are not picked up directly. This makes it ideal for micing the underside of a dulcimer.
Overall, I am very pleased with these mics, to the extent that I will be purchasing a third one soon!