I just posted a few hours ago but since then I got my call saying that my Shuttle 9.0 came in this morning. I literally ran down to the store to get it. As promised, it fits in the same carry bag as the 6.0 and there's no noticeable difference in weight. So, I carried it home and plugged it in.
WOW!!! Even at low volume, (can't crank it up in my apartment

) I definitely noticed a bump in headroom and it's a lot more beefy sounding. I'm sure once I have a chance to crank it up, I'll notice an even bigger difference. Additionally, like all Genz Benz amps when the EQ is set flat, the true voice of whatever bass you're using comes out. I tried 3 different basses and all sounded different.....and crystal clear!
It's funny: I wanted the 9.0 because of this thread. I was lucky because I had just gotten my 6.0 and was able to return it. Now, I may never need another amp ever again!
Some pics (please excuse my poor photography)
http://s1011.photobucket.com/albums/af237/bassnyc1/New Amp Day Part 2/