Not sure what you have to haul, but the Jandd doesn't seem to be very big. I'd make sure your stuff fits before getting it. Not sure how high your saddle is, but the bag bottom dragging on the tire/fender might also be a concern, also there doesn't seem to be a lot of form support. If you have a heavy item it might make that problem worse.
The Carradice bags, and the Rivendell Baggins bags, require a saddle with bag loops like a Brooks, but there are adapters for plastic saddles out there to be had. Good luck.