I'll back Maximus on this, all the manufacturer is banking on is that they'll sell enough of the high priced models to cover anything they pay out and still make a profit. There is way to much amperage in a lightning bolt for any surge protector to stop a direct hit, but the odds of a direct hit are extremely slim.
I've seen sailboats with lightning surpressors on them have a hole blown clean thru the hull from a strike. The supressors used on large craft are huge capacitors with a 02 guage copper wire going to a ground plate on the outside of the hull. If that system can't disipate the strike than your small capacitor and 12 guage wiring in your home isn't going to.
They're going to help in an indirect hit, but in a direct hit the only thing that will save your 'puter is unplugging it. BTW, my roommates 'puter got fried last year from an indirect strike. She didn't unplug hers, still doesn't no matter how many times I got after her for it.