Givi.
Just come back from France today. Totally waterproof, unfortunately! Could have done without finding that out.
Appear to be substantial, as when I pulled out from parking on the pavement in Caen, ( common thing to do apparently} I forgot the panniers and hit a post, only just caught the bike as it started to topple. Right testicle not thrilled with close aquaintance with petrol tank though!!!! Only went with the top box loaded, and a couple of locks in the panniers, but the idea was to be able to lock away the leathers and have casual clothes to wear. I would recommend this to anyone, being stuck in hot leathers aint no fun. My mate only had a tank bag so I was the load bearer.
If I had been using the aluminium panniers (too dear for me) I would probably have come off, as the Givis are chamfered on the leading edge, & I bounced off as opposed to grinding to an abrupt halt.