I listened to the advice here and went with an Ortlieb bag, and it's pretty swell.
I bought a Ortlieb Downtown Commuter Pannier with the QL3 mounts
My rack works with it, but there is no real love. It's an old "Delta" that I think I got at REI.
I have to mount the QL3 entirely on the top rail of the rack as the struts are in awkward places.
This leaves the bag higher than I'd like (harder to toss a leg over, higher center of gravity), and also means I have to have it farther back than I'd have it if I could angle it (covers rear light too much)
I want an Ortlieb QL3 Friendly rack that fits disc brakes. Not costing a zillion bucks would be a plus.
The Axiom DLX Streamliner Disc Cycle Rack is in the running, but I really have no experience with picking and want to make a good decision.
Tubus seems mighty expensive.....
Hints? Your story?