Thank you for your input. SW Motech is the other locking sadlebag system that I have been considering. I won't be using the bags every day so I'm looking for a system that looks good when the bags are off the bike. I'm not a big fan of seat straps because they don't provide much support. The SW Motech support frame Is a bit more visible with the additional strut mounted to the passenger footpeg mount and the triangular frame extending over the chrome grab rail. The Unit Garage frame mounts behind the grab rail with horizontal bars extending parallel to the grab rail. This two rail frame design does not obstruct the lines of the grab rail like the triangular SW Motech frame does, but the SW Motech's three pin bag attachement system looks very secure. Both systems sell the bag attachment plates separately so, theoretically, the plates could be attached to just about any bag.
The SW Motech bag design with modern hardware appears to be more advanced than the Unit Garage bag.
Maybe the best setup would be the Unit Garage frame and mounting plate with the SW Motech bag?