One of the things I like most about Shure mics is, what you see is what you get. They are generally simple, effective and the term robust doesn't go quite far enough in describing how well made they are. Al of this describes the SM 57 perfectly. It is a very standard looking dynamic microphone and although it is designed more for instruments than for voice I find myself using it often when I need a mic for vocalisations. This is mainly because it has a clear pick-up with a short range so I can grumble like a troll into it and it won't pick-up the noise of the air-conditioning unit in the background. I am not sure how useful it will be for location recording and sound effects, but I am happy to test it out.
Over some time the SM57 definitely confirmed itself as a useful mic for vocalisations; be it goblin or pixie the SM57 handles vocal ranges and sounds very well. Its obvious strength is for instrument miccing as that's what it was designed for. I seldom use a single mic when recording instruments, but I will almost always have this mic in there somewhere. Where it was surprising was for sound effects recording. It deals with high SPL sounds better than I had expected. I haven't yet placed it right at the muzzle of a gun, but I suspect it would deal with it pretty well. In many other situations it is well capable of capturing clear samples of quite loud sounds. I would not choose it for very subtle sounds, but its general recording capabilities combined with it being almost indestructible earns it a permanent place in my kit bag.
In the real world
The main selling point for the Shure SM57, as well as it's sibling the SM58, for my purposes is the combination of very low price and very high durability. A piece of equipment built as sturdy as a Shure microphone allows you to utilise it for more precarious situations without being concerned for the equipments safety. The low pric also means that should something unexpected happen it is not going to break the bank to replace.
I try to be extremely careful with my equipment, but there are times when capturing certain sounds lends an inherant risk to the equipment you are using. The SM57 allows me to work without
Very good vocal / instrumental mic
Great price for what it is
It won't suit every purpose
Not really suitable for very quiet sound sources