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.