I'd definitely go with DisplayCal... I compared profiles and color accuracy between the native Spyder color tools and DisplayCal, and DisplayCal was considerably more accurate.
I just posted this in waterscapes.... but it looks like it likely belongs here.
Shot this a few years ago on my 40D.
Camera Canon EOS 40D
LensSigma 15mm
Focal Length15mm
Shutter Speed1013/25000 secs
Aperturef/22
ISO/Film100
There are always good reasons to shoot in various modes.
P-mode is fantastic when run-and-gunning a live event where light is constantly shifting as well as the subjects. Where shutter speed or aperture effects aren't important to the shot.
A-priority is great for various reasons especially...