I've also heard that the Ortlieb harness isn't that great. Haven't tried it myself though.

OP mentioned he wants a system with quick on/off. I'd skip anything that has velcros, zipties or bungee chords then. Quick release systems such as Ortlieb's allow you to put the bag on rack and remove it with just one hand. It doesn't get much easier than that.

If you find a nice, affordable pannier with no quick release, it may be possible to retrofit it yourself. Rixen & Kaul have the Klickfix, and I remember seeing some pannier manufacturers sell their mounting hardware separately.

--J