Re: Recording Gear
The SM57 has been an affordable staple for recording live music for a long time for a lot of musicians. The MK4 is a side addressable mic that makes draping in on an amp a little easier. Note also that the MK4 is 3 times the cost of the Shure.
Both are excellent mics and I am sure you will not regret buying either.
You may want to tell people what your end goal is (i.e. is this the first one of many, are you just starting out, what your budget is, etc) and you will get some good advise.