Men's haircuts are one of my favorites. There are tons of stylists out there who are afraid of doing them because you can't really hide any mistakes in a men's cut. My awesome husband was my very first client when I was going to beauty school. I think it took me 2+ hours and about 4 haircuts (in the same sitting) to finally get it right. I've come a very long way since then. My adorable husband doesn't get much say these days in what his cut is going to be. I usually just do what I want and experiment on him.
I think the most common sin I see in men's cuts are that it's choppy and not blended at all. This is what happens when you get a 15 min clipper cut (FYI I spend around 45 min-1 hour on a men's cut). Clippers are a fine cutting tool, but most people doing them don't go back and blend it all together and that's why you get those choppy lines in the back. Another thing I see is taking the hair line up too far in the back. I swear some stylists do this just so you come back in 3 weeks because you think your hair is all grown out, but really it's just a neck trim that is needed. You want to work with the hair line as much as possible and not take it up too far just to make it square. And for what it's worth it's not easier to do a men's cut and that is why I don't charge different prices for men and women. I probably spend more time actually cutting on a men's cut because most women just want a trim of an inch or two and I spend the rest of the time blow-drying. Now here are some of my favorite looks for men.