There's a reason every mic cabinet has at least one of these (and if it doesn't, it should).  This is a great all purpose dynamic mic, I use it for instruments, vocals, even field recording sometimes.  The SM58 has a frequency response that is supposed to be more tailored towards vocals, but that doesn't mean that the 57 can't handle a voice.  They're pretty much the same mic as far as I'm concerned, and for the average amateur recording engineer or home studio practitioner I think you'll find the same thing.  And if you're operating at a level where you refuse to use them interchangeably, then you probably already know what you're looking for.  I'll be getting a 58 to add to my personal cabinet soon, but if you're like me and wanted to spend more on a nice condenser before filling out your dynamic mics, you can't go wrong here.