It would be interesting to compare which are the most favored settings for the assignable switches on PMW350 and 320, and for which kind of job.

Mine are assigned like this on the 320, and I do mainly concerts & events:

switch 0: Focus magnifier
switch 1: record review
switch 2: zebra
switch 3: turbo gain
switch 4: cache recording
switch 5: record

I would have liked to assign a switch to 'peaking' but unfortunately that's not in the list anywhere...

How about yours?

Nobody wants to share their settings? Big secret, huh? :-)

No big secret, we now know what you use and we will now all use the settings :-)

Without being specific, mostly I find my preferences for 'normal' assign buttons are determined by two things -- how often do I need to make the adjustment, and how worried I may be about hitting the button while rolling (and this screw something up).
Hence I tend to not have as part of my 'normal assigns' things like Turbo Gain, Cache Recording, or even record -- unless I'm pretty sure I'll be using them that day.
My reasoning -- if the camera rubs against something and/or I hit the wrong button -- how much will things get messed up by that? Having extra record buttons is convenient, but hitting one by mistake turns the camera on (or off) at the wrong time! I recently got a call from one of the companies I work with asking why one of their four cameras was stuck on free run time code - I took the lucky guess that someone had programmed 'cache record' into one of the assignables, and the button had inadvertently been pushed, which was what had happened. (they are a company that almost never uses cache record). Similarly, hitting a 'Turbo Gain' button when you really want to be changing your viewfinder could have disastrous effect on your footage.
It's also a good idea to label assign buttons if the camera is used by various people - it can reduce potential problems when they are used to a button 'always' preforming a certain function.