I have loved BtVS nearly all my life. I first starting watching it when I was 10 years old, and haven't been able to stop watching it ever since. That's 13 years of rewatching and rewatching BtVS. When Angel came out I was super excited to be able to add another show to my obsession. Unfortunately, it just didn't click with me. It wasn't because it was darker, or that I was to young to "˜get it' as people have told me (I was heavily into Hitchcock, zombie movies and any type of horror).
There was just something about it I didn't like. Every year or so I would catch half an episode, and try desperately to love the show "“ it never grabbed me though.
I joined the Buffy Boards about 3 years ago and of course was catching bits and pieces of the storyline here and there, never worrying about spoilers because I didn't think I would ever watch it. It all sounded stupid to me "“ Angel and Cordy together? People think Wesley is cool? Angel has a son? A singing green demon? Of course that put me off even more. Then one day I came home to the Season 1 box set that my boyfriend had bought for me.
It sat around gathering dust for a little over 6 months before I was hungover enough, and lazy enough to just reach for the first thing I could find. I was GLUED to the entire of Season 1 and of course then wanted to watch the entire thing. It's no BtVS, and I think that's what you have to remember going in to it. It's a different show, with different themes, and different characters really. (Angel, Cordy and Wes on AtS are miles apart from their BtVS counterparts)
I think Angel takes a lot more concentration to watch then Buffy, most episodes aren't easy watching like a lot of episodes of BtVS are, and unless you're talking about Smile Time or Spin the Bottle, it's not the kind of thing you can put on for a pick-me-up.
And at the end of the day "“ if you don't like it "“ don't watch it!
Or "“ do what some friends of mine have done, and start by watching the cross over episodes so you have the familiarity of Buffy, Harmony, Spike, Willow or Oz.