For sheer/shear (depending who you talk to!) cutting, the edge would be better either straight or convex. A concave edge would make it more difficult to control which part of the edge was in contact with the wood.
Taking this a stage further, I prefer the gouge edge to be at less of an angle. I go for a "standard" bowl gouge with a 48° bevel (around 50 is close enough!) and around half that angle for the sweep back on the edge so around 20-25°. However, I don't generally use that for sheer cutting on the outside of a bowl, just for push cuts (which if done properly leave a clean enough surface to not need any sheer cutting) and mainly for cutting the inside of the bowl.