I've used both the VO Campagne and Ostrich handlebar box/bags. The Ostrich is larger and all of the closures are the elastic loop type, which I prefer as they can be opened and closed with one hand. The Ostrich is about 30% more. On the other hand, the VO bag's top "hinge" is on the front of the bag. The Ostrich's is on the side closest to the rider. I prefer the former.

A stem mounted decaleur would work well on your bike.