A picture tells a thousand words, but I would still like more words in this review. In the interest in spurring more conversation, here is my critical impression from looking at those pictures:
I may be way off base here since I haven't seen these bags in person, but from looking at the pics, they just look CHEAP to me. They don't look like they are made out of the quality PVC-coated nylon or PVC-coated polyester that real whitewater river-running dry bags are made out of. I'm used to the quality of river dry bags made by Sotar, NRS, and Jacks Plastic Welding. They also look like they are assembled without attention to detail on the seams and patches where the straps are attached. It looks like the cut edges of the material will fray because they are not fully glued down. The main straps also look narrow and cheap.
Based entirely on pictures, they don't look to be the quality of Wolfman Expedition Dry Saddlebags nor the Ortiebs. The problem with the Wolfman and Orliebs is they are too small for me, so they is why I am interested in the Nelson Riggs.
Everything is temporary.