I got panicked into going to a Hair Club type of place to begin with, without doing any proper research. Luckily the product they sold me, while overpriced and not the top of the range, was pretty decent, but I have heard some horror stories from guys who have followed that path. So my top tip would be to do your research, ask lots of questions on places like this, and have a good idea what you want before you buy anything. Second, trust your own judgement - you might think these salons would be experts, but in fact my experience suggests that a guy who has been a wearer for a few years will have more knowledge and better judgement than most stylists in salons. Nobody is as concerned about your appearance and reputation as you are.
Are you considering a system?