After checking the shure site, I'm left scratching my head. Looking at the spec sheet it looks like a sub-cardioid, not an omni at all. Its been my experience that its not very directional. I was wrong in calling the 58 an omni, but I know I'm not wrong about the applications man. I could get my facts right all day long, but in the end, its like Andy says, its just a mic. They use different capsules, and sound totally different, and if you can get your snare to sound sweet with a 58 and a Mackie, or a 57 and an API 312 in the end it doesn't matter.