What are some alternatives?
When comparing Simplified Tab Groups and Conex, you can also consider the following products
Simple Tab Groups - Create, modify and quick change tab groups. Features:
Tabs Outliner - Next Generation Session, Windows, Tabs Manager and a TooManyTabs Solution That Really Works.
Tab Workspaces - Organize your tabs into workspaces.
Panorama View - Tab Groups with Panorama View. Lets you easily Group and manage Tabs visually, with tab hiding.
Tree Style Tab - Tree Style Tab is an all-in-one Firefox extension that provides ability in order to operate tabs as a tree.
Tree Tabs - For better customizing tabs in Firefox.