This is an old thread, but I just wanted to warn people that this Avenir Excursion 2.0 QR bag is absolutely not waterproof, as my smartphone and ipod can attest after being blasted this weekend on tour!! I took the bag home and did some testing in case I had not zipped it up correctly, and it's definitely defective. In light of the pool of water that accumulates in the bag (presumably through the zipper seams as the material is clearly waterproof), you'd be better off leaving its contents out in a rainstorm than keeping them in the bag. The link in the thread is dead but here is a similar one.

It's a nice bag, it mounted easily, and I'm sure it's "water resistant," but not waterproof, which is a shame because of the needlessly heavy material (Tarpaulin?). If you own this bag and plan to get it wet, bring along a grocery bag.