Color output is a matter of driver settings, no printer will give top quality results with default settings on all media types except by accident. Whether it's discs, photos, or documents, you gotta tweak.
The Pixmas have 2 paper feeds, auto-duplexing, solid drivers and software, inexpensive inks, and the list goes on. The only shortcoming of the Canon disc printing software is the limitation to 118mm. Apart from that, there's no reason to use anything else for discs with a Canon printer.