1) Beards are too hot for the summer. They might get a little warm sometimes in the hot weather, but they're also protecting your face from UV rays. In addition, if you grab a spray bottle and give yourself a nice misting in the beard, it will hold that moisture and actually help keep you cooler.
2) It's itchy. No, it's not. Maybe in the early stages before the hair grows away from your face. But once it gets longer, the itch disappears.
3) Beards grow at a uniform length. Sorry amigo, but your beard hair is going to grow at all different speeds and lengths. Let it grow and you can always shape and trim to give it a nice uniform look.
4) The best beard is a full beard. Guys, the best beard is the beard you love and fits your style. There is no "best beard", just the best beard for you.
5) Beards are dirty. Sorry doubters, but beards have actually been proven to be cleaner than completely-shaven faces. Take that!