An experienced sky diver, can make quite an untidy exit from the plane, as long as he is in the correct body position when the parachute opens. In a balloon emergency, don't worry about such details. The moment you are clear, pull the ripcord.

Don't ever "count to 10" - you will have dropped 1000ft.  After about 10 seconds a jumper has reached a terminal velocity of about 120 miles per hour, and has fallen 1,000 feet.
   From then on it takes about five seconds for each one thousand feet.  
  Unlike today, landings were usually hard, so solid boots with ankle support were needed. A crash helmet was essential as well.      

A sport parachutist can reach excessively high speeds, well above normal terminal velocity.
It can be dangerous to open the parachute at such speeds (although much better than not opening)

    Balloonists should have no reason to delay their opening for more than a few seconds.
   The parachute opening can be quite a savage impact, especially on the groin,   however, it is always welcome.
  
   Without that impact, the next one - ?