Most of them don't work, and they smell like the unwashed urinals at an interstate truck stop. Unless you're looking to hook up with a middle-aged, female truck driver with a mustache thicker your own, (:P)save your money.
It's all hype and false science. First off, I used to use some called Realm when I was like 19 and it smelled good but didn't work any better than any other cologne. In fact, I find that I have a better time without cologne, and just scented body wash for the last several years. I have read and been told by professors that this doesn't work. For one thing, the phermones aren't human pheromones first off. They're animals. Secondly, it would take so many pheromones that the cologne would cost an exorbitant amount. The funny thing is that all of the stuff we use to make ourselves smell better actually cover our own pheromones. That's because they're in our sweat. With all of the anti-perspirants and cologne, you're just masking the actual pheromones you have. Good luck with whatever you buy. I would say, if you're going cologne, get a more trusted high quality cologne that works just as well.