I was using Wicd as a backup, as in some hotels, NM was having serious trouble staying connected. Wicd was almost as much trouble as NM was when it was acting up.
My mother-in-law has a Mac wifi router that wouldn't connect to NM at all (I resorted to a mini-router plugged in as wired).
I've recently switched distros (Fedora->Debian), and went with Xfce, and dropped Gnome. Without NM, Wicd seems to work flawlessly, and connects to the Mac equipment without blinking.
Wicd has been stable on my system for over a month.
Anecdotal, and doesn't in any way help answer the actual question... but there you go.