I personally did not do well on it, my energy levels dropped and I lost serious performance in my strength workouts. I did lose nearly 2% body fat (9% - 7.25%) but didn't feel good about it. I do far better on 5 balanced meals a day personally. 

In fact only one out of 7 of my staff made positive changes. She did however increase the amount of coffee and green tea consumed daily in order to keep energy which could mean in order to keep your performance levels up with IF you need to supplement more with ergogenic aids which could be a draw back depending on who you are or how you react to substances like caffeine. 

I think it could have a place if done right and with proper supplementation but who ever is doing it should have a good grasp on their own ability to listen to their body, otherwise it could be a lesson in how to lose performance quickly. 

I think IF is perhaps another fad, but with more research and experimentation it could prove me wrong and become a viable tool to put in the box of nutritional options for clients.