I have almost the exact same experience as Phil in that my 98 had
initial problems but once sorted out has been fine (although Volvo
did not solicit me to purchase the extended warranty on my 98 and
they did on my wife's 95 850).

If someone drives Camry or Accord now then I would not recommned one.

If they are somewhat into cars and don't think of cars as appliances
then I would recommend one. Just check the service records and look
for repeating problems. Initial problems that were fixed once should
not be too big of an issue.