Given that in combat, shield regeneration (apparently) is nerfed to 10% of what most people think they will be getting, it is almost worthless to have shield regenerators on a ship except for bringing shields back to full, 'outside' of combat. (The exception would be if you expect to spend many minutes in combat with pirates for instance, that do relatively little damage.) In the case of a slugfest duel between evenly matched ships, I have to wonder what would be best for the same mass,...
Shield regeneration versus armor hitpoints
Shield regeneration versus armor hitpoints