Fan for the IC = worthless
Fan for the AC condensor = awesome
I removed my stock fan a long time ago. I have a fan for the AC for low speeds. Any speed above 30-40mph, the truck is pushing a ton of air past the IC.
Granted this is an opinion. There are many of us that don't run a stock fan on here. If you are one of those who for some reason can't run without the stock fan, I don't care and I don't want to hear about how your truck over heats. Every truck is different.