From my perspective, as a helicopter pilot working on the North Sea, a watch is very important to me and there are various features which I value. I have tried many different things over the years, but there are a couple of things I can't really live without. Obviously it must be a reasonable time keeper and be reliable. The first is surprisingly maybe to some - a date feature. In todays flying, there is so much paperwork to fill in, before flight, during flight, after flight, and it always requires the date. I know, I should be able to remember the date, but.......Anyway, to me, no date - no good = pass. A day is a nice extra as well. An adjustable strap, not bracelet is also a plus for me. I spend from october to may wearing a thick survival suit, with thick neoprene cuffs, so the watch has to go on top. Everything else is a a nice to have. Sometimes it is nice to have an alarm, as I quite often get stationed away, and I need an alarm to wake me in the morning, although I always have a phone. I don't think i have ever used a stopwatch feature on a watch in the cockpit, as it is far easier to use the one in the aircraft, although a divers bezel is very often useful. I definitely cannot hear an alarm in the cockpit over the 2 CT7-8 jet engines above me, and all the avionic cooling fans surrounding me, so a countdown alarm is useless.
It must be comfortable to wear, very robust and not be a constant snag hazard and wearable in and out of the cockpit. The last thing I want is to dislocate my shoulder trying to put my survival vest on! Finally it must have the personal "x-factor" to me, and that is highly personal. It must be added at this point that the "x-factor" reserves the right to override all other criteria! The watches I use regularly are Rolex submariner on zulu strap - this one has been with me a while and saw active service strapped to my wrist for a tour of Iraq some years ago, and is close to perfect. A Sinn 356 has come into use, although works well with day/date, is not as robust as the sub. My Fortis B42 Marinemaster on a Toshi strap is also damn near perfect. Big, but not too big, bright, easy to read, day/date, great lume, bezel, and looks great, comfortable. I tried for a while with a ProTrek, but just couldn't warm to it. It is a great outdoor watch and regularly comes with me when I am hiking in the mountains, but seriously lacks the "x-factor" for me, and is just too damn big, although suprisingly comfortable.
Other watches i would seriously consider as contenders would be top of the list Rolex explorer II, as it adds the gmt function. I really like plain, simple robust watches so the IWC Mark XVI is also a good bet, but actually I think the Timefactors Speedbird III is a better watch, with all the same benefits, but added robustness due to lower price, better anti-magnetic properties, and better water resistance. Also Fortis B42 day/date Flieger.
So that is my take on it.