As a banjo player...
I started out using SDCs on stage. If the sound guys didn't have one, I used my MK-012. However, after getting tired of hearing "you guys sounded great, but I couldn't hear the banjo" I decided to take matters into my own hands.
So, I bought a pickup from pick-uptheworld.com, along with one of their preamps, and haven't looked back. I'll turn the preamp about half-way up for the sound check. During the show, when I get the squinty-eyed "I can't hear you" look, I crank the preamp up some more.
I'd prefer to work a SDC when playing in a live bluegrass/folk context, and still do sometimes -- when the FOH guys know how to work with stage condensors -- but, usually end-up using the pickup.
BTW, the pick-uptheworld.com pickups are the most natural sounding I've heard, and the preamps are exellent for live work.
- Jim