The goal with Mockup was to build a clean, fast, and super easy-to-use theme with great touches throughout; be it the multiple layouts (with per-post overrides), the quick and elegant animations, the reader-friendly comments area, the un-missable (yet optional) featured story area, custom profile page backgrounds and descriptions, the customizable elements etc., Mockup is well thought-out, crafted with care, and suitable for many purposes.
To go in-depth and learn more about Mockup, please do have a look around the demo sites. Here are a few quick links to get you started: features, layouts, gallery, formatting.