The Good:
For a place that looks like it's all about cool -- the distressed wallpaper, chandeliers, a certain amount of Gothic splendour -- the staff are very friendly, cheerful and helpful. Coffee or tea as soon as you sit down (and maybe a glass of wine if you've been there a few times) doesn't hurt. Generally, my haircuts have been great, and that's with a head of fairly unruly wavy hair. I've also brought my kids there and they love the stylists and have received great cuts. Great products too.
The Slightly-Less Good:
If you're a boy, make sure to ask for one of the stylists that likes working on men's hair. The one less-than-perfect cut I got was when I was pressed for time, couldn't get one of the great men's-hair stylists and took a flyer on someone else. My fault for bad time management more than theirs.