One more note and regarding performance.
Non-persistent php mysql connections can be just as fast as persistent conections provided your mysql server is tuned correctly:
my.cnf: thread_cache = 16
The thread_cache value in my.cnf must be configured to a value just high enough so when viewing statics, mysqladmin extended-status, "Threads_created" value does not increase during peak hours. Do not set it too high and suffer wasted cpu cycles.