This bike is in a different solar system than the Miyata.
It looks like a fillet brazed frame and possibly EL-OS ? judging from the big tubes and oversize headset. That is a very nice frameset . Because the frame tubes are large, this bike could be a 53c , maybe even a 54 depending on how it is measured
As well, looks like a unified Campagnolo build kit in very nice condition. The only thing odd about this bike is the stem choice, but that was probably done to suit someone who needed the bars higher to use the aero clip ons