I have lots of 57's old and semi-new and they can vary a bit with age / abuse i have found.
I have a bunch of old "May" mics from the 80's that were in my drum kit, they obviously did not put transformers in them, and even when i was a kid starting out i knew they did not sound like a regular 57 on my kit. Back then a engineer friend of mine back then mentioned that they sounded "fatter" than a 57......... little did i know back then why.
I did a comparison in the Gear Shootout forum of a normal 57, Transformerless 57 & modded 57..... you can listen and see what they sound like on different instruments.
We did this for our own purposes......... Just because we love hearing things for ourselves.
SM57's Modified & Stock Tests