Here's Jim Williams on this mic over at Gearslutz:
"A great mic. The familiar square metal diaphram casule. It uses an EQ network to lift the tops flat as the capsule has a high end roll-off. The quality of that network is critical for top end clarity and detail. It's a op-amp based circuit, using fet input opamps. I've replaced them with BurrBrown, AD opamps with great results. The coupling caps can be replaced and improved.
Jim Williams
Audio Upgrades"
The thread is:
http://www.gearslutz.com/board/remo...2970-milab-vip-50-general-usage-opinions.html
I guess there's room for improvement in most mics, especially in the amplifiers, until you get to the very highest end pieces.