I've recently replaced my OE panniers with Givis. While my Suzuki plastic never opened in transit, they were a bugger to close and I never really had confidence in the latch. Also, while in theory they are only 1l smaller in capacity than the Givis they are such a stupid design with the latch intruding so far into the pannier so as to make them seem 10l smaller. I know Givis aren't the last word in aesthetics (E36/E45) but at least they are sturdy and you can be sure that they are closed. And they are a damn sight cheaper (or is that less expensive?) too.
Salut!