navigation - Are hover menus in headers easy to use?

Do users find it easy to use headers/menus like the one displayed below?

Answer

You get better performance if users click the menu bar to open a menu rather than simply hold the mouse pointer over it. Hover-menus were demonstrated to be a bad idea long before they appeared on the web:

Chaparro BS, Minnaert G, & Phipps C (2000). Limitations of using mouse-over with menu item selection. Proceedings of the Human Factors and Ergonomics Society Annual Meeting, July 44(2), p361. (nearly full text at Mouse-Over vs. Point-and-Click: It Depends! )

They're also inconsistent with the tried and true DOD Design Criteria Standard - Human Engineering (aka MIL-STD 1472):

5.14.2.1.8.4 Explicit actuation. A separate, explicit action, distinct from cursor position, shall be required for the actual entry (e.g., enabling, actuation) of a designated position

However, once a menu is opened, it is preferred that additional menus open on hover. For more details, see Make web menu bars more usable.

Part of the issue is that to get accuracy as good as click-to-open, you have to put in a delay that’s so long that any speed advantage of opening on hovering is negated.

Hover-menus are a textbook case of an intuitively appealing idea that fails in practice. They're also a textbook case that just because something is common on the web doesn't mean it's a best practice.