I've got the best of both worlds.
Viscous fan & shroud as well as the factory switch in the top of the radiator, which brings the electric fan on just before 3/4 temp.
Engine temp will sit on 1/4 normally, then with the A/C on in heavy traffic won't get over 3/4 because electric fan is on and viscous is locked up.

Also note, that when I had AU electric fans on and it was a hot day, the fans were struggling to get below 1/2 temp. Therefore constantly staying on in traffic.