was thinking of running to bass pro shop and picking up the 598 hd si finder but it only has one sd slot compared to the 798 hd si. was wondering what that would limit me to do with it. i could live with out the preset buttons i think?? but if theres some big loss in map usage/ waypoint saving ability I think id try and go with the 798. but would like to save some dough.eventually i would like to get a map card,but having that in the 598 , would that limit my ability to save waypoints to sd card???? hopefully you understand what im getting at. And for me this is a major investment and want to be satisfied with the purchase.