Well, ok, an update: Cinnamon breaks BADLY with the most recent Nvidia 
drivers. Add to that, it does irritating things, with either overriding 
some Xorg settings, and (at least the HOW of) its use of Xorg settings in 
its own settings (I had lots of fun getting my trackpad to work 
predictably). Solutions, from around the web, for solving the Cinnamon + 
Nvidia debacle, range from such magic, as install bumblebee, and *MAGIC*, 
cinnamon will suddenly work, to reinstalling Nvidia drivers, from the 
Nvidia website and *MAGIC*,  Cinnamon will suddenly work, to reinstalling 
your entire Linux setup and *MAGIC*, everything will just work. Yeah, no 
thanks.

Anyhow, I've ended up happily chugging along with a 
lightdm+openbox+compton+thunar stack. Quite happily.
Add tint2 and kupfer to the equation, and it's a golden setup, which 
behaves just as expected- as configured. 
When you're going to set things via config files, anyhow, you may as well 
go all the way, and go with the solution which operates almost solely 
according to those configs, without adding so much cruft atop them.
Lessons learned!
The only two bits of cruft, in my current setup are obconf and 
lxappearance, as they do make setting the general "look and feel" stuffs 
easier. And lightdm appears to work easily with whatever you put behind it.