I haven't tried em... but what can ya say... once you reach a certain price point and quality level it's kinda subjective as to the strengths and weaknesses of equipment. You're talking personal preferences in sound which varies from person to person. One of these days I've gotta grab a Neumann u87 though.. I've heard about them for so many years that I have to get one just to see what all the fuss is about. :)

I bought one piece of software that might interest you, called MicMod... Antares I think? You tell it what mic you're using and the distance you're singing from, then ya pick from a list of mics that you want it to sound like (like neumanns etc..)
It's obviously not going to give you the quality of the real thing, but it's a good way of comparing the strengths and weaknesses of a whole bunch of different mics. I use it occasionally as an EQ. Sometimes you can't get the right sound no matter what you do, so you try it through a bunch of different emulators until you find one that fits.