Personally, I've tried both products on the market for two years ie 90 Pro Performance Nutrition and this one.
I have not been disappointed by these two products are really great.
The gold standard is generally less than metered Pro 90.
For cons, the taste is lighter and less pronounced, which is more pleasant to use.
The Gold Standard is cheaper than Pro 90.
For a quality / price / performance, I would say that Gold Standard is very well placed.