Do a search on here. You'll find a gazillion posts about them, both pro and con.
The one in Middletown opened a little before Thanksgiving, I think. There's one on 35 in Little Silver that's been open for about a year and a half, and one in Ocean Twp near Seaview Square that's about a year old.
Five Guys is the largest of the "better burger" chains, according to an article I read recently, with about 450 locations.