The main thing to look for when you're looking for protein supplement, is if it's 100% protein. There are many low quality "protein" powders that claim they give you great results but then when you look at the nutritional value, you see that they have more carbohydrates than actual protein.
Look for those that are as close to 100% protein as possible. I personally used Optimum Nutrition protein.
Personally, I cannot really say what results I had with it because I always had a pretty strict diet anyways and consumed enough protein from food sources. But well, it definitely tasted good, was relatively cheap and I heard lots of people praise it for its high quality.
Yeah, so I'd still get my protein from natural food but if you go for the supplements, then look for the "pure" 100% ones ;)