I've used em for audience mics to great effect at shows before - they capture every last detail of spread out sound. They did do well on vocals and things until I upgraded to better mics, but I had wished I'd just spent the money on a better single mic for things like acoustics and vocals.
I know that's pretty much always the case, but you'd be well served to do some more research. They might be the most-sold mic on musiciansfriend.com, but high sales don't always mean quality for the cost. They do things well, but you can do better for around the same cost, imo