Many consider the Retina IIIC (Big C) to be the ultimate Kodak Retina. Certainly, it was the last of the line for the folding Retinas.
With its large bright viewfinder/rangefinder and single-range selenium meter, it was an improvement over its predecessor, the Retina IIIc, which certainly was no slouch.
The satin chrome finish on the later Retinas was much improved and even better on the Big C models (and also the IB).
As with the other Retinas, it will happily knock out photo after photo without even breathing hard. The Xenon lens performs excellently, although some feel the f/2.8 version holds a slight edge over its slightly faster f/2.0 sibling. Either is capable of great results.
As with all of the later Retinas, the film advance lever is on the bottom of the camera, and the film counter is subtractive.
The single-range meter was an improvement over the meter in the IIIc. There was no longer a need to flip up the flap and try to figure out which scale should be used.
Like the other B/b and C/c models, the camera used the Exposure Value system, which is either the best thing or the worst thing ever created. It's easy enough to ignore the EV system altogether and set your own exposure.
If you want the ultimate Retina, get the IIIC. But beware, the collectors have been pushing up the price.