I don't mean to promote my little shootout, but I've compared the two "57's" (along with 4 others).
The shootout's only on cabs, not snare, but if you're familiar with the Shure (or any others in the shootout) you can see how the GLS compares.
Here's the link to the main page (the pages with the sound files are listed at the bottom):
http://www.spottedmuse.com/shootout/
so this would be a decent choice to mic up some toms/snare with? i need some sort of mics to replace my shitty CAD tom mics. would these be a good candidate?