Rated 3 out of 5 stars

An excellent, time-saving add-on with macros automating routine tasks. One MAJOR complaint - when moving form version 4 to 5,t the single most useful feature allowing PrefBar to be relocated next to the main Firefox drop-down menus, thereby giving considerably more room for the Firefox browser window - this feature was inexplicably lost, much to the dismay of many. Even though this issue has been widely discussed, the developer has seen fit not to fix the problem. Beware the loss of browser screen space. Consider uninstalling version 5 and replacing with version 4 until the problem is handled

This review is for a previous version of the add-on (5.1.0). 

This still works. It just works different, now. PrefBar cloned a Firefox feature for a long time to keep compatible with SeaMonkey 1.x. As I dropped support for SM 1.x, I decided to drop my duplicated code and use what Firefox and SM 2.x already has: The built-in toolbar customize feature.

So to move PrefBar's stuff to the menubar, do the following: Enable PrefBar (F8), right-click on the menubar and choose "Customize...". Then you'll see an item "PrefBar toolbar items" lying on PrefBar's toolbar. You may move this via drag&drop to the menubar or anywhere you want it.

Result would be the third screenshot:
http://prefbar.mozdev.org/screenshots.html