I believe the most important thing is the refresh rate. I use a
Suunto while paragliding and it works great. The last two altimeter watches my wife bought me didn't work well because after a few minutes in the alitmeter mode, they would only refresh every two minutes. The
Suunto I fly with refreshes very fast continuously. I've never looked at the manual, but it appears to take a new reading every 5 to 10 seconds, plenty for general hang gliding / paragliding (unless you like to spiral dive in the fog and need your watch to know when to pull up!!).