I would not go that far. I think Pinarello and Guerciotti were both imported by the same distributor, and they are a bit 'quicker' in handling than say, a 1983-85 Cinelli. My Cinelli climbs well and handles decently. My Guerciotti is noticeably 'quicker' in it's handling. There are a lot of subtle differences in the bikes that make them all handle a bit differently. Bottom bracket height, chain and seat stay bridges, fork design and rake all combine to define the ride characteristics, as well as the frame material.

To me, it is hard to beat a De Rosa as a sum of all those things. They are quick enough for a crit, and smooth enough for a fast century, they climb very well too. The ideal thing is to have a Cinelli and a De Rosa/Merckx. You can have both for what a mid range modern bike would cost.

BTW, the one on eBay is by no means a 1975, and not the traditional 'Professional' model.