The most important thing is microphone placement, quality of the pre-amp, and the compressor if used (both in terms of how well you use the compressor, and how good the machine is) above all else. Even the best microphone won't sound right if you are not using your compressor correctly, or if your mic pre-amps suck.
That said I've tried a number of mikes but in a limited environment. Most were in the mic try-out room in a music store. But when mikes that your have known and loved for years are there, it's easy to talk into your mike and then go compare it to one of the mikes next to it.
I own (among other "lesser mikes" that don't count) some SM 57s and an AT 4033. The SM 57s work great on amplifiers, and do very well on vocals and even acoustic guitars.
The AT 4033 is just a gorgeous microphone for vocals, or almost any acoustic instruments. Just make sure you have a wind-guard! It was a little harsh on the dulcimer, but I was able to fix it with some compression and a little EQ cut. I was astonished at how well it reproduced the stand-up base. It does great for both high end, and low end frequencies.