Technically striker-fired guns have a shorter lock time, but hammer-fired seem to have crisper triggers IMO. I also agree hammers usually provide more energy to the primer, you rarely hear of light strikes with a hammer-fired gun. The visual aspect of "seeing it is cocked" is nice, but some guns like the XD have the pin that sticks out to indicate it is "cocked."
A decock is nice because you can return the gun to a very safe condition for carry, but still have the advantage of a crisp single-action trigger pull. You can carry DA (hammer down) safety off (heavy trigger is safe) and if you need a fast shot you won't even feel the trigger weight, then all the subsequent shots are SA. Some people hate that, prefer to have a compromise of consistent pull, although the pull is never as good as most single actions.