WordPress Options API

Tonight, I have mostly been playing with the WordPress Options API to create some admin pages for my theme. I was pleasantly surprised by how easy it was to create the admin pages and associated custom options. I think I’m going to be able to have a lot of fun with these.

My only concerns with using these custom options are:

1. How do they impact on performance?
2. When should I use them in a theme, as opposed to a plugin?

I guess I can test the performance impact, but I’m thinking that caching will negate any concerns I might have. With regards to my second concern, I’m thinking I’m probably the only person to decide this and it’ll depend on how self-contained I’d like my theme to be.