All shocks will eventually fail in tough offroad conditions if they're overloaded/undersprung or badly setup (rebound/compression damping).
To cope with corrugations the suspension will require different settings than for any other situation.
I disagree with some of the opinions here, but that only down to my personal experience and those I've travelled with......
So would say, most reliable is possibly a new OE shock with an uprated spring but that doesn't answer the question of an improvement on corrugations where a quality shock such as a well set up Ohlins, is by far the best.
Other than that as I'm sure you know, corrugations need to be ridden at the optimome speed for a particular shock setting.
As for an air shock, if it fails at all you're fecked unless you carry a steel bar to hold the bike up.