I would only fly nonrevenue standby during off peak times. I have, many times, with my family flown as an employee and we always go off season. So far we've never had any problems, but as a standby passenger you always need a plan B or even C. I work in a major hub so there are plenty of flights every day. As a general rule, I always try to take the first one of the day, because that is the one people are most likely to miss. Then they will be put on the standby list for the next flight, ahead of employees.
Much of flying standby is timeing. Stay away from week ends and holidays. If you desire to go during the "in" season I would look into buying a ticket.