The notion that condensers are unsuitable live is an oft-misguided myth. You'll find that professionals frequently use condensers in concert/broadcast situations. It's all about proper mic positioning, correct gain structure and common sense (on part of the band) to not blast amps/monitors. For example, my drums are miked with almost 95% condensers (whether live or in the studio). Same goes for loud 4x12 guitar cabinets. I would not hesitate in using hand held condensers for vocal duties.
Metallica (as you mentioned) are one of Audio-Technica endorsees. Some other notable AT endorsees include Linkin Park, Evanescance, Good Charlotte and mony more. All these bands are known for their great live sound. You will not find any Shure of AKGs on stage.
The new wireless system from Line 6 looks interesting too - runs on the frequency of 2.4Ghz and has "mic modelling" technology.
Mic modelling technology is frowned upon by professionals. The idea that you can make a SM58 sound like a high-end condenser is ridiculous. If I want to "model" a mic, I can get the similar results using EQ. Choosing a microphone has always been an application specific matter. I'd rather pick the best sounding mic for let's say, the particular vocalist, not rely on a "chameleon" mic that only gets me halfway there.