Depending on the powder, charge volumes can and do vary greatly.
One example:  ‘max’ load of Auto Comp is 60% fill, whereas Blue Dot ‘max’ is 103% (compressed load obviously).

Specificaly as it relates only to case fill percentage/volume... are there benefits/drawbacks to one extreme or the other?

Thanks Aero.
I too like the ‘safety margin’ of full (or close to it) to reduce the potential for double charges.
Knock on wood... I’ve never had a double or squib.  But I’d rather not start now if course

Pretty much this.  Fast powders that can easily double-charge and maybe not even be noticed, are a significant Kaboom risk.  Also, I've always been a believer that a full case means no variability to how the powder lays, which makes for more consistent ammo.  In a pistol, for most people, does that really matter?  That said, I find that really slow powders usually don't burn very clean or consistent, and tend to throw a lot of powder around, on your arms and in your face.   For this reason I tend to prefer more middle-speed powders, like HP38, CFE Pistol, AA#5, Win 231.  I find that slower powders like BlueDot just spew powder everywhere, and result in a quickly fouled gun.  Just my preference.

As others said, being able to catch a double charge easily is great about more fill. I use Titegroup in my .40 USPSA loads, and go significantly slower then when loading say my 9mm loads with power pistol.