I have both. The Riggpacks are easier to secure to the rack on my A but I like the Grantour better. Ridding Solo, I put the riggpack on the rack and the Grantour on the passenger seat. (after modifying the tiedown). The Grantour mates up so well, I have to remve the included backrest to fill up.Riding. 2 up for any distance I prefer the Riggpack. They both hold about the samebut the Riggpack has a snap on rollbag that holds extras, Camera shaving kit etc.
I've got a Nelson Rigg trunk style bag. If had it for one year and it's already starting to fade to the purplish black the same way the HD bags do. Functionally, its great, easy to mount and take off, holds a ton of stuff.