The first season is at least. I've always preferred Angel as a whole over Buffy. The characters tend to be more dynamic and the world is more mature. Also, as someone once said, Angel is the best Batman movie ever made.
Linked above is the best episode of season 1, wherein Angel and Wesley are called in to exorcize a home.
"We can't bust heads like we used to, but we have our ways. One trick is to tell them stories that don't go anywhere. Like the time I took the ferry to Shelbyville. I needed a new heel for my shoe so I decided to go to Morganville, which is what they called Shelbyville in those days. So I tied an onion to my belt, which was the style at the time. Now to take the ferry cost a nickel, and in those days, nickels had pictures of bumblebees on them. Give me five bees for a quarter you'd say. Now where were we, oh yeah. The important thing was that I had an onion on my belt, which was the style at the time. They didn't have white onions because of the War. The only thing you could get was those big yellow ones."