It depends on the person. I find both Quick Looks and reviews to be useful tools when deciding on which games I want to buy. A Quick Look gives me a better impression of how a game plays and looks than a review does, and reviews delve deeper into a game's underlying mechanics and (usually) offer an opinion from someone who has beaten it.
Also, a 3-star game means it has some faults that only certain people can look past. The problems that irked Alex might not have the same effect on you. That's where watching Quick Looks comes in handy.