A note on the leaked AIO tale, that person should be able to claim for all the affected components. A single incident though isn't a rationale for not using them (or as Stefan would say, "Not an argument.") If one adopted that MO, one wouldn't use anything at all, eg. last month a Samsung 840 250GB died on me, but Samsung are still my main recommendation when someone asks about an SSD. However, anyone who says AIOs never leak is indeed talking nonsense, but you're wrong to say "... it's only a matter of time.", that implies such a failure is inevitable, when in reality the vast majority of users are more likely to upgrade or replace their system (and/or cooler) long before such a fault has any significant chance of happening.
I've used about seventy coolers so far, including a couple of dozen Corsair AIOs (and a fair few of them were used/refurb), no issues yet. My favourite is still the TRUE Rev C though; one of these, single fan, 2700K, M4E, 5GHz no problem, nice & quiet (though in final builds I use an H80 + 2x NDS PWM).
I'll use an air cooler where an AIO would be overkill (eg. 4.7GHz 2500K system I built last year, TRUE worked great), but an AIO does also help for far more secure transport, especially international. Big air coolers can be banged around too much (not an issue of course if the system will be stationary).