Remember the key to the Panamax is removing applied voltage in case of major line fluctuations (high & low), not just spike suppression. I believe the limits are 97 and 137 volts.
This is where conventional suppression does no good. Think of line spikes as major noise and MOVs as supression for 'that' noise.

Panamax also rates their spike protection circuitry as having something close to infinite life for all pratical purposes, barring direct lightning hits, etc.

It's quite ingenious in it's function, a nice design for a fair price. And again, I think a minimum for any home theater system.