Morning gents. All depends on the context. If you're a pub band playing small stages with amps and drums just behind you and shouty stage monitors, a really sensitive mic with hi-fi top end will be a bitch. If you're in a more hifi environment with ear monitors and some space on stage, then you would want a nice sounding mic and you can get the most out of it.
The venerable SM58 is still great and I have a few. But it's quite a dull sounding mic up in the nice pretty airy frequencies, although it's got enough midrange brightness to but through a band. They are indestructible which is quite excellent. The beta58 is louder, more output, tighter pickup pattern, and a big crunchy frequency spike to make it sound brighter. I hate them, although some people make them sound great. I do like the beta57 however.
Great small/loud stage mics: Shure SM58 or beta58 or beta57, Audix OM5/6/7, Sennheiser e845. All should be around your budget.
Great nice sounding mics: Telefunken M80/M81, Sennheiser e945, plus tons and tons of nice expensive Neumann, Shure KSM, etc, etc.
My picks -Sennheiser 945 for nice hifi sound, Shure Beta57 for LOUD stages, Shure SM58 for BV's and what have you.