I've actually never really watched Angel, maybe I now will since its getting good word of mouth.
See what makes Buffy stand out as a TV show for me was the incredible dialog it gave the characters. I liked the early seasons much more than later ones.
The Willow Lesbian angle was a bit much but the show had the courage to try things like that. I seem to recall the episode where Buffy's mom died as being another standout depth wise.
And it did have that really cool Emmy Award winning episode where the tall, dark and gruesome butlers stole all the sound in Sunnydale.
That was a cool concept that made for a really interesting episode that was more like a silent film than anything else. And yet they made it so that you could still understand everything the actors were feeling and thinking instead of having it simply run as a silent hour of solid action scenes.
This all said I've only seen a handful of episodes of Smallville, but what I have seen has struck me as pretty basic stuff. I mean I saw one episode featuring three super vixens out to get Clark. It seemed closer to Charmed than anything else, and making me think of Charmed gets it zero points