A wide variety of opinions exists on how inspectors should comment on Federal Pacific Stab-Lok electrical panels. The more definitive an inspector's comment is, the more he opens himself to liability if, in court, he were asked to prove assertions that FP Stab-Loks represent a significant safety hazard.
The following in-depth paper provides a wealth of information on these panels: FPECircuitBreaker Hazards- J. Aronstein
The Consumer Product Safety Hazard Commission decided that a definitive study was too expensive to complete. Read their statement here.
I recommend the use of the following narrative(from the InterNACHI Narrative Library):
"The electrical service panel was a Federal Pacific Stab-lok model. These service panels are reputed to have a significant rate of circuit breaker failure that can result in fire or electric shock hazard. For safety reasons, you should consult with a qualified electrical contractor to discuss the necessity, options, and costs for replacement. You should contact your insurance company to confirm that this panel will not be a barrier to obtaining a policy. Information about Federal Pacific Stab-lok panels is widely available on the internet."
This comment can also be used for Zinsco, Sylvania, Challenger, and Westinghouse panels.