I have been riding this 96 diamondback parkway, 700c wheels too, for over a year now, as my commuter.
I also have a 1980 soviet racer which is not ridden too far, because I felt the lightest gear is still to heavy on climbs. (43/17) The parkway weighs 17kg, while the soviet start syosse is 13 kg.
But...
things are changing.
I have put a single speed hub on the soviet racer, now it is 43/20.
So now I FEEL I can go faster on the soviet racer, even though it is a single speeder now.
I have put only one cyclocomputer on the parkway, none on the racer.
now I prefer commuting on the sovietski steel.......
So, one must try different bikes, to really feel differences among bikes...