Mechanical Fan VS Electric Fan
Nuker, you and I have the same philosophy... build it for 100k miles, drive anywhere at any time with anvil-like reliability. We just go about it with different methods. On my build, I'm using Spal dual electric fans with a fan controller set up for 2-speed operation to minimize amperage draw and noise.
http://www.forabodiesonly.com/mopar/showthread.php?p=1057036#post1057036
Although for reliablility, I agree that a mechanical fan/clutch assy. is hard to beat but I think electronic equipment is pretty reliable these days for the most part as long as you use a quality manufacturer. Almost all new cars use an electric setup these days and you know the manufacturers don't do something unless there's some benefit to it (although the benefit is sometimes due to packaging issues.)
Hey how about a thermostatically controlled hydraulically operated fan?