Summary: Please note that this review is based upon my experience with this printer in Mac OS X 10.8. This review will likely not be typical of Windows users, so if you're a Windows user and are looking for a nice MFP, PLEASE don't let my review sway you away from this printer. There are plenty of other reviews here to give you a good idea of what you will experience as concerns the Windows OS.
Good printer but don't buy until you price the toner
Jeffrey Cross, Amazon
5 January 2013
Summary: After 6 months, we have replaced this printer because of ridiculous toner prices. You have to choose $80 Canon 128 toners or cheap after-market toner. Read the reviews - the Canon 128 gets very limited page output for a VERY expensive cartridge. So, we tried two brands on after-market toners. Both produced unacceptable output. Don't buy this printer without researching the toner cartridge cost and reviews.
Summary: I purchased this product to replace and older Canon MF4370DN - which I loved. I took the older Canon to our weekend place - but will be bringing it back to my home office! Anyway - I bought the D550 for the ADF function. Alas, the ADF doesn't like more than 4 or 5 pages in a row, then it jams up by taking two or three pages at once. When you clear the jam, it cancels the job. So if you are doing a 20 page job and it jams up on 18 - so sad.
Summary: This was a Gold Box Deal from Woot on Monday, September 10, 2012. Let me start off by saying the Canon D420 is an attractive machine and appears to be well built. The unit was packaged very well and arrived quickly. I think it may be an older style, the product manual is dated 2008. The trouble for me began with attempting to install the printer/scanner software on my Mac Mini, 2.26 Core 2 Duo running Lion 10.7.4.