I can speak for the IPF 9100, it does a very nice job with B&W images using the Canon driver. I did a lot of testing with the Bowhaus RIP for Canon (Mac Only), and while it could make a beautiful print, there was zero correlation with a calibrated monitor, so it took a lot of tests to get to a good result. For me, not worth the effort.
Most of my business involves pretty large runs of prints for trade show displays, which really go through a lot of ink. The heads seem to go more than a year in most cases. A few have quit before warranty, and Canon replaced them with no hassel. Our second Canon printer, an 8000s, died a few month ago and the cost of the fix (we'll send a technician and fix it for $1500) was not acceptable, so I'm in the market for a new machine soon. I don't think a three year old printer should die, and I've not found an option of fixing it for around $500, which is all I'll go. The life of a machine is also a major consideration, and I'm a bit dissapointed in the Canon regarding only a three year lifetime.