I like the SM57, too, but once you try a decent condenser, you'll hear the detail that you've been missing. It really depends on the style of music how much detail you want.
The quality and type of preamp makes a big difference, too. At each stage, there is an opportunity for distortion and loss of fidelity, and when you combine a low fidelity microphone with a low fidelity preamp, you're really losing a lot of information. That's why the SM57 CAN sound really great when using a high end preamp. That's why I will use condensers for vocals, but dynamics for other instruments where detail isn't as important. That is, until I can afford a Grace Designs 101...