I'm adding a luggage rack to my Tour Pak on Thursday and I need to pick up a rack bag. Just going by the numbers, the Kury GranTraveler is the biggest by far (2.3 cu. ft) -- the next closest bag on my short list is the Rack SAC at 1.8 cu. ft. Most everything else is in the 1.2 to 1.4 range. Is the Kury really that much bigger than the competition? Hard to tell from the online pics and I don't have any dealers close by to see them in person.

 

I have the T-Bags Roller Dekker and it has 2.6 cu. ft. storage area for $159.

 

I have the Gran Tourer bag and love it. On and off in a snap. Very secure attachment. Holds quite a bit. I usually use it for mine and wife's leathers and chaps, as well as a few other things. Side pockets handy. Easy to roll around (have to take off one of the side packs to roll though - no biggie.) Rain cover works good and it's attached so you won't lose it.