If NM 0.7 hasn't worked for you, and you're using upstream in-kernel device drivers (not -staging crap), then I'd love to hear from you about what your problem is. If you're using NM 0.6, you probably want to upgrade to a newer distro or version that uses NM 0.7.
*Most* of the problems NM has are caused in whole or in part by bad drivers, and that's why its important to have the code so we can fix those drivers. Binary drivers, on the other hand, cannot be fixed, and no maintainable solution can be had by working around their bugs.
And of course there are bugs in NetworkManager, and features that people want that aren't yet implemented. For example, when the wifi connection fails (timeout, AP forcibly disconnected you, you loose signal, etc) nm-applet will pop up the "Type In Your Key" dialog. People hate that. I understand why. The underlying cause was either (a) the driver failed, or (b) the key was wrong, or (c) the access point is crap. So I'm going to work around that by making NM Just Try Harder.
But there comes a point when Just Try Harder fails, because the driver or hardware have problems, and NM just can't work around it any more. Then we get to fix the driver anyway, which we should have done the first time around anyway.