Not a miracle pill, but it does work
I've gone on and off this a couple times in the past year or so and thought I'd share my findings.
It seems like one of the big claims with this is that it helps you gain mass. I weigh myself every day and have never found that to be true beyond maybe a pound or two. I also have a naturally skinny build and use protein mass gainer and keep my water intake high so maybe I'm already at my max weight, but I don't think you should look to this to gain mass.
As for increased outright strength, I know quite well what my max's are for things like bench and cleans and I don't feel a difference at the same weight while taking this vs not taking this.
The difference I feel that convinces me that this actually does something is the increased energy I have. I don't mean energy to do cardio, more like my desire to do some finishing cable exercises when I've already been at the gym for an hour. I notice that while taking this I seem to take less time between sets because I'm not as worn out at the same weight. I can still do approximately the same sets on this or not, taking this just makes it easier.