I used to have the topeak wedge dry bag, and it was really good – waterproof, easy to close and roomy (I had the large) The only downside that I found was the the rivets that attach the mounting bracket to the bag, eventually worked their way through the body of the bag. Given that I used it predominantly off road, it was pretty predictable. The strap mounted version probably not suffer from this, but I prefer the convenience of the quick release bracket, so that I can switch tge bag between bikes easily.
I changed to the Ortlieb bag (medium) a few years ago, and it is showing no signs of breaking at all. The one tip I would give for these is, after rolling up the closure – and just before clipping the buckles together – twist them in opposite direction, preventing them from unrolling.
Final tip for both – either pack them fully, or line with foam rubber – as they have a hard plastic body, and things can rattle around.
Would be happy with either, to be honest.