Caveat -- I've never shot any of the little pancakes on my Nikons but did extensively in large format days, so that said some generalizations. Tessars generally have good to very good optical performance on centers and then taper off smoothly toward corners, with the size of the sharp central circle getting larger as you stop down -- common spherical aberration falloff. Spherical aberrations will produce "swirlies" in OOF areas containing linear patterns. Wide open the sharp center is usually pretty small, like maybe 1/3rd the frame; by f8 - f11 it should pretty even performance across the frame. The Voigtlander version uses an asphere element, so probably performs better/renders an initially larger sharp central area, but again that's conjecture on my part, not empirical.
As an aside, I believe the Nikon P (for pancake) is the same design as the earlier GN (for Guide Number) designed to be used with manual flashes of the day -- have not looked, but the GN is probably less expensive used than the P for the same look, though it has a funky aperture ring with guide numbers stamped in it.
PS: I got to spend some time viewing Bob's images this week with the new 58/1.4G. I have newfound respect for this lens' performance compared to other posted images I had seen, perhaps sample variation. Anyway, somewhat ironically it exhibits similar behavior to a Tessar the way it falls off, though in this case far more subtle. Blister sharp ⅔ center with smooth and subtle falloff toward edges, with amount of softness attenuated gradually outward as you stop down.