That's strange, since GNU/Linux and OS X both (last I checked) use CUPS for printing.
That said, it really depends on what printer(s) you buy. I've had wonderful experiences with HP printers, and tend to recommend them. Brother, Konica Minolta, and Epson printers work reasonably well with some tinkering and research in my experience.
Is there any sort of certification scheme for CUPS? Given that's the standard for Mac and Linux, I'm surprised companies don't make 'CUPS compliant' printers.
I see a lot of recommendations for Brother printers, but they seem to require quite an involved process to set up.
That said, it really depends on what printer(s) you buy. I've had wonderful experiences with HP printers, and tend to recommend them. Brother, Konica Minolta, and Epson printers work reasonably well with some tinkering and research in my experience.
Canon? Godspeed ;)