1. Browser boot time.
2. Browser shutdown time (on clicking Close).
3. Tab boot time.
4. Tab shutdown time.
5. LocalStorage boot time (on first call to LocalStorage API, some browsers load LocalStorage into memory at this point, blocking the UI).
6. IO performance of LocalStorage, WebSQLDatabase, IndexedDB for massive get/set operations (bandwidth) and many get/set operations (latency).
7. ApplicationCache update time (and update time after an interrupted update cycle).
8. Smoothness of moving a DOM element across the screen by adjusting absolute position (some browsers are choppy with this).
9. Javascript parse time.
10. Minimum setTimeout frequency (is it 1ms or 5ms?).
11. Hash change event propagation time.
12. Stack size limit.
13. Speed of Array.shift on massive arrays.
14. Vertical height of browser chrome at top of the window in pixels (less is better).
15. Vertical height of browser chrome at bottom of the window in pixels (less is better).
16. Number of colors used in browser chrome, including favicons in location and bookmark bars etc. (less is better).
17. Fullscreen support and switch to fullscreen time.
18. Developer Console boot and shutdown time.
19. Number of words, tabs, nested interfaces used across all Preferences pages (less is better).
20. Number of user actions (clicks, keypresses, mouse movement distances) required to clear LocalStorage, History, WebSQLDatabase, IndexedDB, Cache, ApplicationCache (less is better).
21. Default storage limits for LocalStorage etc. (higher is better).
22. Data-URI size limits (higher is better).