K-9 Mail vs. Shift

K-9 is an opensource email client based on the Email application shipped with the initial release of Android. K-9 is focused on making it easy to chew through large volumes of email.

Shift is a customizable browser built for people who live in their browser all day. Unlike standard browsers, Shift lets you drag and drop apps, bars, and controls to build a layout that actually matches how you work. Choose from 6 starter templates or build from scratch. Either way, you end up with a browser that fits your workflow, not the other way around. Whether you're a freelancer juggling clients, a remote worker managing multiple tools, or an entrepreneur running several projects at once, Shift gives you the flexibility to shape your digital workspace around your life.