The powder tastes aweful but is more economical, doesn't matter which.
Poliquin use to recommend .17 grams per kilo of BW, but he has doubled that subsequently.
For BF loss, it's recommennded to take prior to a W/O (about 10-20) minutes) to convince your body that muscle tissue has already broken down, prevent further catabolism, and hopefully tap into FFA's.
To forstall the onset of fatigue, one would take some about 1/3 of the way into a W/O and then between sets.
There was a study posted at sprortsci.org not long ago