Just bought one today, Ed, and getting used to it at the moment. I was going to go for the Pixma Pro 9000 Mk II but couldn't really justify the extra £200, and have always been slightly wary of Epson printer heads blocking (I've had Epsons before, albeit a long time ago)
The few prints I've done (mainly 4x6 on Canon Photo Plus Glossy II paper) have come out pretty bloody good, to be honest - not that I've had a real chance to see the results in clear dayight. But so far, I'm impressed.
It's fairly quick, fairly quiet, easy to set up straight out of the box...
For some reason, I find that it prints better with more realistic colours from Aperture than Photoshop, but that could well be down to me not knowing how to set up the colour profiling correctly, or setting up the image parameters themselves from within Photoshop.. I'm not sure yet. But so far, as I say, I'm quite impressed.