supervisord is a delayed curative solution as it's not integrated in
the solution. It has to check availability of the solution at a
certain frequency. FPM supports this natively which makes it a real
time curative solution. More over, FPM can stop requests which take
too long time, this is a preventing solution also. Definitely FPM is
the best option. BTW, FPM will be included in the next PHP release
(5.3.3) which will be available soon (in the next comming weeks).