I've got the KTM bag. Works well enough, and none of my stuff has gotten wet with the rain cover on.
I do have two gripes though-
1) The funky angled shape (short at the front, deeper at the back) sometimes makes it difficult to carry much stuff (or oddly-shaped stuff) in it. I know, I know, that's why I have a rack, but when trying to put a pair of sandals, a sweatshirt and a few snacks in the bag, it gets a bit unwieldy. Granted, that's a function of the design/shape of the bike, but there it is...
2) The expansion capability is nice, but it really doesn't like to be half-full. Expanded, anything less than fully stuffed, and the bag gets wobbly and unstable. Not nice. I suppose for a trip I could cut some polycarbonate to give it some structure, but for general running errands, it can be a bit cludgy.
That being said though, I'm going to stick with it. It's like the Aerostich suit- not perfect, but under most circumstances, it works well enough to make up for the few flaws.
I just twist and my eyes glaze over, "uh....errr huh huh, weeeeoooooh---doo dat agin, doo dat agin..." -morriswf
I like my women like I like my instant oatmeal- quick, easy, and covered in facts about dinosaurs.