I've worked with Telefunken and all types of Neumanns, like U87, etc. that fit the high price range (between $1,000-$5,000) and the lower-end, from the whole list of Shure mics, M-Audio, Audio Technica, etc. and I've found this:
If you buy a really pricey mic, you need a really pricey preamp and compressor, point blank. And if you use a pricey compressor with a low-priced mic, you can make it sound like a million bux along with some good EQ down the line when you're mixing.
But in terms of comparing $50 mics to $200-$300 mics, there's not much to compare. Read as much as you can in terms of reviews and ask people who are doing the same thing as you, and you'll make out. And remember: used mics can sometimes sound as good or better than new mics, ESPECIALLY if the person who is selling it has no idea about its capabilities, and just doesn't know how to record. I had a guy who got rid of a Shure KSM-27 for $70, pretty much still-in-the-box, and the 27 is about $500 something list, but you can get it new for like 300. Anyway, the kid who bought it was asking me about mic techniques, and I helped him buy a compressor and a tube amp, and the mic sounded better than most for tracking hip hop. After explaining that "it sounds like shit and I need to get rid of it", the original owner was dumbfounded on how we got it to sound so good, and the new owner even rubbed it in his face by sending him a sample of his vocal recording. The old owner asked if I could help with his setup after that.
Sorry for writing a damn story, but don't listen to what the manufacturer says about their microphone, especially if it's under $500-$1000. Listen to the people who use it, on forums like this one or reviews of the products online, and figure it out yourself with trial and error. When a manufacturer graphs out that pretty little "frequency response curve", take that as a general reference for how it will sound. You may look at the picture and say "Hmmm... that <b>HAS TO</b> sound good, because it ranges from 20Hz to 20kHz and just <b>LOOK</b> at that <b>WARMTH</b> between 3-5kHz!!!" No. Never judge a mic by how it LOOKS.
But anyway... here's a list of some mics that have really worked for me in the past, greatest to least:
<a href="http://www.zzounds.com/item--AUTAT4033CL" target="_blank">AT4033"</a> - about $400, but you might find cheaper
<a href="http://www.activemusician.com/p/EM_SHU-KSM27-SL.asp?ref=fg" target="_blank">Shure KSM-27</a> - about $300 give or take a couple bux
<a href="http://www.sweetwater.com/store/detail/NT1A/" target="_blank">Rode NT-1A</a> - here for $200, not a bad deal at all
<a href="http://www.sweetwater.com/store/detail/AT2020/" target="_blank">Audio Technica 2020</a> - slightly cheaper, but good tho - here for $100
<a href="http://www.zzounds.com/item--MDOLUNA" target="_blank">M-Audio Luna</a> - about $200. I have this mic and it works wonders for me. You can even check out a vocal sample <a href="http://hypnotixhiphop.tripod.com/sitebuildercontent/sitebuilderfiles/dearfather.mp3" target="_blank">here</a>. (This was recorded with an Art Tube amp and a Alesis 3630 compressor.)
And I would avoid these microphones, from personal experience, but some may disagree with me:
AKG C2000
AKG C3000
Blue Mics in general (waste of money for what you can buy for cheaper)
Shure KSM32 (for some reason to me, the 27 sounds better and it's cheaper)
There are a few more, but I either forget, or I haven't played with em enough to give any advice on em.
Hope that helped, and sorry for the short story if you weren't looking to read one.
Pce