Cost, about 20 quid.
Dual time zones (one always on zulu). Alarm & stopwatch and countdown.
Gains 1 second a day (reliably).
Used for diving to 40m and timing astro fixes as well as all the usual pilot stuff. Over a year at sea, racing and cruising.
A previous version broke at something above 50,000 feet when the glass popped out (intact), presumably due to pressure differential as there is no screwdown. Other than that, no problem.
Needs a new battery every 5 years and a new strap every 2.
Of course, one uses a genuine mickey mouse watch to time-hack big formation briefs, just to annoy the mud-movers.