OS X is sweet: it's simple and intuitive, and I think GNOME shares a lot of values with it.
Nat FriedmanRed Carpet Enterprise has been really well received since one guy can install it in about an hour, and it makes it trivial to deal with software management issues like deploying updates and creating standard package sets for your various machines.
Nat FriedmanBig Linux deployments have reached the point where it's become a real problem for administrators that they don't have nice tools to manage their servers and desktops.
Nat Friedman