Dickson's Hairshop on the LES is cool. But you have to book in advance because it's tiny and they fill up quick. I used to go there regularly. If you're in Williamsburg the Beehive is good. Staff is nice.
Those are on the pricier end. Well, not so pricy for NYC. They're like $40. It's not like going to Bumble&Bumble. Now I go to George's 2 in Park Slope because it's $12 and as long as I tell the guy everything to do it's just as good as any other spot I've been to.
Never liked Astor. Always felt like their top priority was getting you out of there as quickly as possible.