Most comments comments mention Brother, but for me, Oki is working like a charm. Using a B431dn (b/w, duplex) and a C531dn (color, duplex) with PPD files from OpenPrinting. Older models though, not sure if Oki dropped quality in favour of DRM since.

Rules of thumb:

1. Laser instead of ink unless you specifically know that you need/want ink.
2. Stay away from HP, Canon, and probably Epson. HP, like IBM, has long lost its aspiration for quality.
3. Stay away from anything that is ‘smart’ or ‘cloud’.