I guess it depends on how you define "ballistically superior".

It's similar to the 6.5X55 Swede.

My notes say that a 145 grain bullet is launched at 2,600 fps and 2,178 ft-lbs of energy. That's about 2,950 Joules.

My notes for a 140 grain bullet from a 6.5X54 shows about 2,500 fps and 1,950 ft-lbs of energy, or 2,640 Joules. So the Gibbs would be faster, and has a little more energy.

More accurate? I don't know. Downrange performance (drop, drift) would be heavily dependent on bullet specs (Ballistic Coefficient, Sectional Density). About all I can guess is using the same bullet in each, the Gibbs would be a touch faster. But I don't think a deer would notice the difference.