It's not one size fits all.
I use coconut oil for cooking meat.
I use butter for vegetables.
I use ghee for frying eggs, and in Bulletproof Hot Cocoa.
Butter has a better taste because the milk solids provide some sweetness, but ghee is better for hot temps.
5'0" female, 44 years old. Started Primal October 31, 2011, at a skinny fat 111.5 lbs. Low weight: 99.5 lb on a fast. Gained back to 111 on sugar cheat. Currently fighting off sugar/candy cravings with bulletproof cocoa and a little rice.
I (try to) follow by-the-book primal as advocated by Mark Sisson, except for whey powder and a bit of cream. I advocate a two-month strict adjustment for newbies. But everybody is different and should tweak Primal to their own needs.