I used to drink bulletproof coffee hoping for more sustained energy in the morning and I found no difference between the bulletproof version and regular coffee.
First, the amount of caffine is the same. Bulletproof coffee doesn't have anymore caffine than regular. Granted, I didn't purchase the actual bulletproof brand, but I used organic coffee, organic MCT oil, and organic grass-fed unsalted butter. The premise is that the fat should low for a more sustained release of the caffine, along with the fact that your body needs certain fats to function properly.
While it didn't taste bad (surprisingly), I didn't notice any difference other than the fact that I consumed 400 calories before I actually ate any solid food. I'm short and I only have 1500 calories a day to work with if I want to remain at 110lbs. I did not have any extra energy, not did the caffine effect me longer. I drank this every morning for a month to give it a chance. It did absolutely nothing different than an ordinary cup of coffee and seriously skewing my dietary macros meaning I essentially couldn't have any other fats the rest of the day.
Unless you don't like eating and need to gain weight, this is a waste of time. Go with Priest's suggestion.