The LBS where I worked during the boom was a Sekine dealer. They brought out the SHX with Dura-Ace in 1973. At the time, I was on (Nuovo) Record. As noted, your typical cyclist couldn't tell the difference, except in the wallet,. At the time, Dura-Ace was about 60% the price of (Nuovo) Record. Besides the price, the Crane rear derailleur used on the Dura-Ace group shifted better. I also liked the slightly larger shift levers. (Nuovo) Record did have slightly better bearings, harder races and harder chainrings. There was also a matching seat post and pedals, which Dura-Ace didn't introduce until later. However, there was a Dura-Ace freewheel that was far superior to the Regina that typically came on Campagnolo equipped models.
In my region lots of cyclists replaced the Universal centre-pull brakes on their otherwise all Campagnolo bicycles with Dura-Ace. Campagnolo was just too expensive and they liked the fact that the levers were drilled. Some, like me, also switched to the Crane rear derailleur and Dura-Ace levers. I knew others who used all Dura-Ace bicycles except for Record wheelsets. Many who raced Regina freewheels were often tossed, in favour of Maeda and, to a lesser extent, Dura-Ace. (Nuovo) Record far outnumbered Dura-Ace in the mid to late 1970s races in which I participated. I'd estimate it was 20:1. maybe more.
I did end up getting a Sekine SHX but the frame couldn't match my Scapin, which I continued to race with Campagnolo and Shimano mix. Regardless, I had no issues with the Dura-Ace, outside of slightly higher wear rates on the chainrings and bearing races. I had more (Nuovo) Record failures but never had warranty or small parts issues.
IMO, Camapgnolo's (Nuovo) Record series defiinitely has the higher prestige and higher resale value over !st generation Dura-Ace. Similary reduced Super record occupies the same position over 2nd generation Dura-Ace EX and 3rd generation Dura-Ace AX, though I consider the latter to be grossly under rated. Shimano finally gained parity, arguably superiority, with New Dura-Ace (7400 series) in 1985. Cyclists had been berating Shimano for quirky features and New Dura-Ace was largeely a return to basics, at a time when C-Record started to embody quirky designs.