I prefer the "button on the trigger" as on my Valmet O/U. I'm trying to get used to the tang-type selector on my Gold Label, but don't really expect to have to select on most upland shots. (Getting the safety off smoothly is enough work for one old thumb!)

For ducks and for "blocking" positions on pheasants, you have time to select and a selective trigger is helpful, if you only have one trigger. For pure upland shooting, I just leave the selector alone and shoot the open barrel first. I don't seem to have problems moving from double trigger guns to single. (Or maybe that should be #12231 in Armstrong's Database of Wingshooting Alibis).