Sometimes technical, sometimes not, never a kitty

How does the source code and functionality of the beerhouse compare to community server?

Codewise, they are totally different. Beerhouse is a starter kit, and and is meant to be a "how-to" example. Beerhouse can be used in production, but isn't necessaruly meant to power a large community. Both have a lot of features, many the same, you just need to see what works for you. If you're planning a large community with blogs, galleries, and forums, you want Community Server.