The one that I have on my K6 is already 5 years old and handy for town riding. Just enough space, also it is narrow and less wind resistance. As stated can take a full face helmet plus gloves. I place my air pump inside the helmet, so it is available when needed.
Bottom line, it is cheap yet serviceable. For those long trips, I change over to the Givi (plus panniers or saddlebags), which can hold a lot more items when touring. Yes, before you ask, I have to change the top box base-plate, but that is quick. I view it as part of prepping the bike before any long trip.