I have literally tried every type of protein out there over the years and the blended proteins have produced the greatest results by far. As Kenny mentioned, buying Whey and Casein protein separate and mixing them yourself are a great option which I have also done. Or you could buy a blended protein. The taste and price determine which of the two I buy. Optimum nutrition is a good quality brand protein to go with if you're mixing Whey and Casein. If you're going to buy a blended protein, I would go with Syntha-6. As far as getting advice from a store employee, I wouldn't because they'll tell you anything to sell more products. Best thing to do is research and read yourself. Also trial and error is what I live by to see what my body responds to.
Anything worth having is never easy to achieve.