I've had a Blackhawk for about 5 years now, and here's my 2 cents....

-keeps time: excellent. Once when I was really bored, I did the 'track via "atomic" time to see if it keeps accurate time' bit, and it hardly lost or gained a second throughout a week. A month later, it was still within a second or two.
-design: the plasti-rubber/steel bracelet is a letdown; if they offered a pure steel band, I'd go with that. Normal wear and tear of day to day wear led to the near breakthrough of the plastic (polymer?rubber?compound?...whatever...not the steel part) portion of the bracelet. Taking it in for a battery change, they broke the band completely, but paid to replace it. If it's on your wrist, it's durable...just don't put it in an envelope and then jam it into a briefcase.
-durability: excellent. I'm too chicken to actually wear it in a SAR operation, or any field use where it could get broken in a...uh...'non-compliant suspect' arrest. (Department might pay for a Timex...but no way in heck will they foot the bill for one of these.) But it has been around on vacation, surviving bangs that would scratch other watches. The crystal is still perfectly clear after all these years of bumping into the junk I carry on my belt.
-chronograph: keeps perfect time when compared to digital. Mind you, digital *much* more useful and easy to read *all* times. On the Blackhawk, you'll need 20/20 to discern the actual minute and fractions of seconds...particularly if the hands are blocking that particular portion of the watch face.
Since the bezel is marked in 10 minute times, and not a 'real' flight computer, this isn't the watch you want as a backup if you are a pilot who is looking for a flight computer backup. The numbers for those calculations are a bit on the small side...
It's possible though...just not easy.
Also...the bezel has an annoying tendency to rotate a few minutes when you're wearing winter gear and it rubs against your jacket wrist cold-flap thing or gloves. Since it's unidirectional, you've got to crank it all the way around, hoping you don't go one click past 12.
-alarm: mediocre. Not the most accurate thing to set, not very loud. Has limited 'snooze' capacity. When alarm is on, watch isn't waterproof...be warned.
-night use: depends on situation. The illumination is 'painted' on the dials, not little vials of tritium like some others. Very bright when 'charged' (particularly with blue light...mine seems to glow for a loooong time when charged with it). 'Charge' wears off in time...it's much better than those with luminous markings which disappear in seconds. You can actually read it throughout the night. However, say you're driving...the light from various sources will be enough to throw off your night vision, and that glow on the hands, which is perfect for darkness, becomes difficult to read.
-'cool! Let me see that watch, dude! factor' <img src="images/graemlins/ooo.gif" alt="" /> : extremely high. Even if you're dressed very casually, salesmen and casino hosts at certain places realize that you're good for a few hundred bucks, seeing as how you bought a watch like that and will treat you like a sucker...er...like a valued customer...accordingly.

Cons:
-since there's no way to gauge battery life, one day you'll check your watch at noon and see it's five o'clock. Then you've got to bring it to a jeweler for a battery change...and make sure they don't tear the gasket, or waterproof goes out the window.
-bracelet/band isn't very adjustable; you may find it slides up and down a few inches on your arm, or is too tight. I'd get an all steel band if they made one for the Blackhawk.

Perfect watch? Nah...but not bad. The perfect watch would be the Omega X-31 or X-33...whatever...the "Mars" watch...loud alarm, digital displays for variety of info, along with an insurance policy that asks no questions when it's broken for whatever reason. <img src="images/graemlins/wink.gif" alt="" />