I have voted "no" although I would leave it on
 if I had one (the 12-yr/$1200 "rental program" really
 turn-me off though)
  Age: 50 
 Years in the sport: 15
 Number of jumps: 2466
  Consider this:
 1) I always wear a helmet (only 2 jumps have been made without)
  2) I have a audio-altimeter that beeps at 2000ft AGL to let me know whether I need to cut away
 the messy canopy I have up there 
  3) I understand about being knocked unconcious
 during RW. To me this seems to be a very, very
 unlikely event - less likely it seems than dying during 
 the crash of a skydiving airplane
 (there have been many in the last 15 yrs); 
 it is also MUCH less
 likely than being hit on landing final by
 another jumper seeking the same landing spot
  4) At my DZ, most RW formations Im in are 8-ways, not 50 ways
  I know that there have been lots and lots of
 AAD saves - but most seem to have been happening
 because of jumpers not being altitude-aware.
 AADs have been saving many jumpers from themsleves!
   JP