My second favorite is Giant Loop Siskiyou soft panniers. Although both systems are rack-less, they don't have much in common. Mounting is completely different, as well as luggage organization.
There are many good and informative reviews about these panniers on the net, so no need to get into general details here. Just check Advpulse article on them.
What I found important is that Siskyou's have volume of 35 liters per side, 70 liters in total, which is roomy. But more, when mounted onto 1090 Adventure R, entire top luggage rack and passenger seat remains free and flat. So strapping one more large duffle bag, or two, isn't a problem. If I were to go on around the World trip and I wanted to carry a lot, this would probably be my choice.
And they fit KTM 1090 Adventure R (and 1190 and 1290) like a glove. Here are some close-ups of Siskiyou's mounted on my bike. Fit is perfect, bags hug the bike closely and everything is very secure. My bike has Wings exhaust, but bags fit great on bikes with stock can too. Just in case, I always use heat shield.
Brackets help by adding strapping point that is closer to the bike than OEM passenger foot peg bracket, so bags hug the bike better.
Important for off-road, and city traffic - this is relatively narrow setup, more narrow than handlebars in any case.
I have Power Parts Ergo seat on my bike, which adds few cm, so bag sits even better than when OEM seat is used.
Since bags are very adjustable, fit on the bike with OEM seat is great too. Here is how that looks on my bike with OEM seat installed.
It is obvious that I value these panniers highly. From my point of view, it is very close call between Siskiyou's and Reckless-80. Siskyou's have slightly better luggage organization (luggage is reachable more easily) and Mosko's are maybe a bit tougher. But at the end, it all comes to personal preference.