If you caught mesprit with a quick ball you got insanolucky cause I threw dozens at him to no avail. I even damaged him down to red, quick balls still didn't help much.
The "stationary" pokemon like Regigigas, Azelf, Dialga, and others I would never throw a masterball at, not when I could save and retry with more ultraballs. Those pokemon are all guaranteed catches imo.
No, I use the master balls on the wanderers.