Never ever use a flex fan if you tow or drive in mountainous terrain. At high RPM the fan blades flatten out moving less air (for the same amount of drag). So think about what happens if you have to climb a long grade in 2nd gear. Not so freaking good. Electrics are the way to go. Thats why new cars have them (aside from transverse engines). They only draw current when the thermostat demands flow. However, when they are on the alternator load on the engine is close to that of any other fan. Electrics are much better if they are mounted behind the radiator as a puller than a pusher (as a pusher the restriction to airflow is always there fan running or not.)
Also, I have driven cars without engine fans for extended periods of time. I take my truck's fan off for highway trips and it saves about 1 mpg (10% improvement) and a lot of noise. My TR-6 hasn't had a fan in 5 years. Unless you spend a lot of time idling, the fan is just along for the ride.