I have a Canon 6100 and 8300. After a little more than 1400 square feet of printing, both heads needed to be replaced but prior to that it would start doing frequent deep cleanings which waste A LOT of ink. I replaced the maintenance cartridge about 2 weeks ago and it's already used 20% of its capacity with those cleanings (I replaced both heads recently so hopefully that should stop but the printer didn't successfully identify that the heads needed replacing). The 6100 is a backup machine. After 2 years of use I had to replace both heads. I only made about 5 prints on those heads but just out of the warranty, both heads were dead. I keep these machine on 24/7 so they can run the regular maintenance cleanings to prevent clogging. I also have a humidifier in the room to maintain at least 40% humidity. They are well cared for. The heads should NOT have failed with such light use.
Image quality from the 8300 is fantastic but I've been less than impressed with the reliability. Another note, if you use cut sheets with the 8300 it will scratch your print with certain glossy papers (Epson Exhibition Fibre being one of them). In terms of QA, Canon has a very poor ethic (in my opinion) when it comes to quality assurance that is part of the corporate culture (this opinion is based not just on the 8300, but also experience with the 6100, D30, 10D, 20D, 1DMkII, 5D, 1DMkIII (that camera was the straw that broke this camel's back and was the catalyst for me to sell $20K worth of Canon gear and switch my entire kit to Nikon), 24-70L, 70-200 IS L, 16-35 MkII blah blah blah).
I won't say "don't buy the 6300" as there are many folks who are quite happy with it and have no problems. People (like myself) who have had a bad experience tend to be more vocal (normally I'd blow it off, but I've had issues with just about EVERY piece of Canon gear I've owned and I don't think that's bad luck or a coincidence... my most recent find was that they bundled the wrong firmware updater (one that was several years old) with their v1.25 firmware update for OS X). What I would recommend though is calling a dealer that specializes in large format printers, and that sells all of the models you are looking at (like Shades of Paper or Booksmart Studio if you're in the US) and ask them what their thoughts are. If you call Shades of Paper ask for Jason Adams. He's a really straight shooter and he knows all of these machines really well.
Another thing you might want to research.... find out what each company charges for on site repairs after the warranty expires. I'm not sure about Epson or HP, but Canon charges a flat rate fee of $1400 SO... if all that is broken is a $50 part, you're going to pay $1400 for that. If on the other hand you need a motherboard, transport motor, two heads, a sensor, and the front panel assembly... you still only pay $1400. So... there are cases where that's a bargain but most of the time Canon is going to come out WAY ahead on that one which leads to the other thing you should check: Are there any businesses in your area that provide independent repair services for the model you're looking at. If you call Canon and give them your address they'll give the names and numbers of independent repair centers in your area (Canon's support for their large format printers is really superb, that's one thing they do really well).
Cheers, Joe
