[themes] Do you build off of the Zen theme?

I'm wondering what people think about using Zen as a starting theme on which to build other (fixed-width) themes. I remember hearing that some people like it because of its visual simplicity, but I know that its use of z-index can complicate things with incorrectly overlapping elements that have different z-indexes. Is there any consensus about this? I know Hunchbaque is a great place to start but wonder what people think about Zen. Best, Ezra Gildesgame