Did you find the mic preamp to be significantly better than the 900? Also, why aren't you using the 1000?

Sounds like Dave has caught a bad case of "Donnyitis".

Maybe, but I've had this 900 for a long time, and only recently fell into a situation where I don't have to set up nightly. It's pretty cool to just walk in, take off the dust cover, and hit the power button!

Two great questions. Yes, I had a 4x about 2 years ago, but I was doing so many one nighters, that setting up monitors was too much hassle.
Q1: The mic pre is better on the 4x. Maybe not the sound, per se, but there is an extra harmony voice available, and the addition of unison/chorus along with harmonies. This is useful for 4 freshmen/Letterman style harmonies.
Q2: The 1000 has a few cosmetic differences that made a quick swap from the 900 impossible. I use a small DJ style mixer velcro'd above the pitch lever, and there's no room for it on the 1000. I thought I'd lust leave it in the studio for recording, and I still might ... unless I can make a nice swap with someone. Then, the 900 will stay home, and always ready for one night stands.

The 1000 has some great improvements over the 900, most noticeably the screen, but there were real estate issues that trumped the screen.