They are both good companies. I like GP and don't really stray away from them, as long as they have the product I want. I've used them since they came out and haven't haven't been let down. The only way you can know for sure, for yourself, is to try the product for yourself and once you find something you like, stick with it. Thats what I have done and it's worked out well over the years. It's hard to tell from reviews online...cracks me up to look at reviews by some random guy saying that he didnt make any gains on a certain product, when I've taken multiple different batches of that same product, over a period of years, and never had a problem. I'm still making gains and progress every year, using GP.