My choice is not a true 'swingarm' mounted bag. I did have one, but
I found that I needed a bit more storage than most of them offer.
So what I went with is the saddlebag system from the Rocker.
Its also Quick Detach... Here's a few pics.
This one is faux leather with a place to keep your paperwork. Strap keepers are pretty good and it comes with clear plastic sticker material to put on your frame where the straps go.
Here's a pic of my XL Leatherworks swing arm bag. It fits a surprising amount of stuff for its size. It only drags a degree or two before the floorboards, so not an issue really.