I've taken the AM/PM combo twice and take the PM seperately.... buy for different reasons.
-My 1st AM/PM run-- was on a cut, got okay results, nothing extreme or out of the ordinary. It just gave me a little more energy and a PEA "euphoria" feeling
-2nd AM/PM Stack -- didnt try to use it to cut, instead used it for energy and rest.
I saw AM as mediocre, okay for energy, supposedly the shots are better for energy and hit you quicker.
The PM is awesome for sleep and good rest. Its pretty cheap, knocks me out and I usually have some sweet dreams. Its easy well dosed from what I can tell and I grab it when I see it on sale by itself. I'd use it again and recommend it for sleep or rest in general. I can't attribute any fat loss to it, but that said, its hard to cut or bulk correctly without proper rest. But I also think GHenereate and related products are better for the recovery & rest combo.
You made a good decision on the Shift.... you wont really feel much from it since its stim free, but boy does it work. And you can stack it with practically any non-thyroidal fat burner so you are set to have a killer cutting stack.