The SM57 and SM58 are true workhorses. I have some, and have beat them up for years. But to my ear, for acoustic guitar and such, the Rode has a much more accurate and detailed sound. If you are playing an inexpensive instrument, the SM57 may well make it sound better. If you have a really nice instrument, get the Rode. It's a great sound for the money. If you can spend a bit more, the Rode NT3 is even better.