A great advantage of global menus is the ease of pointing them with the mouse.

I was a Fedora user until Fedora Core 6 but the second Ubuntu distribution was a really nice experience so I made the jump (fast packaging system, huge repo, etc).
Since 9.04 (or just before) I have been annoyed by the notification system NotifyOSD, I find disturbing to blur (or hide w/o compositing) the message on mouseover and the popup doesn't provide contextual actions. The Ayatana project get Ubuntu away from the upstream development (many patches to integrate libindicate, etc).