First off, I ran this fan with the stock alternator for years without issues (even with the stereo blowing out tunes through an amp, 4 aux lights on, and the GPS up and running!). Oh, and I ran it with a 40A maxifuse, so no way it is peaking past 40A in real life. You can also get a pulse controller (like Delta Current Controller or Flex-a-lite), which will lower the amp draw at start up (where it peaks).
The advantages of the Ford fan is that (1) it cools better (AC) when sitting still (fan speed does not depend on engine speed), (2) it saves a bit of gas (no need to run the fan when driving down the highway), and you can shut it off for water fording (so the fan will not get sucked up into the radiator). in my case, I run 2 separate control setups, so I use a 3 position switch
ON (top position): turns on the low speed of the fan through a 35A relay
OFF (middle): turns fan off
AUTO (down): runs the DCC box, which adjusts the fan speed according to the radiator temp, and turns fan on at low (lower than the regular low speed) for AC ussage.
Hope this helps!