We have used them for some time and quite often. These microphones may not be as well known as other mics but they of the most realistic sounding clean mics you will ever own. My engineer loves this mic and uses them at all times on guitar amps and acoustic guitar. I used it to room mic some drums and it became my favorite microphone for live drums and for micing cymbals and tom toms.
If you use this for vocals it could work but I have not use it for lead vocals but I have used it in a backing vocal session a while back and it worked great. They have a real flat response but at about 3k they seem to roll off the harsh sounds no matter what the instrument is. Most people have never even hear of this mic. I have used these a thousand times and never have I been dissatisfied in any way shape of form. I used another one for the room and it sounded incredible. We placed the mic about three feet back from the trumpet and the sax and the high mid roll off that I noticed was great for the harsh horns. The sound was flat and sounded fat, crisp and clean. I was using a basic pre amp that day nothing fancy.
I started with acoustic guitar I and I mic'd the guitar from about 1 foot back from the body and used another one from about 2 feet back and the sound was incredible. I recently did a recording session and this was the only mic I used for every instrument aside from drums and vocals. It is very sensitive and picks every nuance up. That is the two best applications I have found with this mic. We have used these mics for years for room sounds and acoustic guitars. This mic has one of the most realistic room sounds around.