[CentOS] Canon PIXMA mg5420 or HP Photo Smart 7520

In need of a new printer, having done a bit or research, and considering 
either the Canon PIXMA mg5420  or the HP Photo Smart 7520.

There are Linux drivers for the Photosmart which are supposed to handle 
both the printer and the scanner.  But in my research I haven't found 
(yet) anyone who's gotten the scanner to work with Linux on the 
Photosmart, let alone the sheet feeder for it.  Allegedly there are 
instructions and requirements for using the fax on Linux.  But I'd like 
to hear from someone who has actually gotten all of this working on 
Linux (either debian or centos) and which version of which distro is needed.

The Canon PIXMA mg5420 doesn't have a fax or a sheet feeder for its 
scanner, but I'm guessing it's even dodgier to get just its single-sheet 
flatbed scanner and its printer working with Linux.  So has anyone had 
success with that?

I've also read horror stories about the how often new ink cartridges are 
required, that basically you pay for the printer a second and third time 
buying cartridges (not to mention how often a print job is interrupted 
by a trip to buy new cartridges).  Any first-hand reports on that?

Whoever thought spending money would be so tough?

Thanks for your knowledge and experience.