I've had some reduced spoke wheels that were bomb-proof (Rolf Vector Comps) and some reduced spoke wheels that were crap (Mavic CXP-22 rims). The crap rims would wobble, shimmy and vibrate. BTW: I weigh 220 lbs.
I've had excellent results with both Mavic CXP-33 and Mavic Open Pro rims with 32 spokes.
As far as failure, chances are that if those wheels give you problems, it will be with going out of true easily or a spoke or two popping. Then you should consider getting different wheels.
However if you ever experience a 'speed wobble' where the bike is about uncontrollable, those wheels could be the problem. If you ever have such a wobble, I wouldn't ride that bike again until the problem is fixed. Of course it might not be the wheels, but it could be.
Lastly there is a condition where a wheel can 'taco' all at once. This is very rare and I doubt that it happens to you.
Thanks guys, I went with the better race wheels not for light weight, but thinking for a cyclocross bike, they would be made for taking a beating. I don't plan on jumping on and off the bike, or bunny hopping like many riders may.
I can't wait until I am no longer concerned about failure due to user weight.