I particularly like Concord fabric and Joan's various lines and have lots of it in the stash. Some I bought at the time and others I find at the thrift store. Although I try to embrace larger scale and modern fabrics, deep down my desire and stash is for a lot of "tiny vine-y" traditional calicoes and that's what I bought 70s-80s... Concord fabric and Dual Duty thread pretty well sums up decades of my quilting.
I agree that it was acceptable quilting quality fabric. The feel and weave of the greige goods (the raw cloth) is good, and especially for the 1980s, about the same quality as Hoffman who had more expensive dye/color saturation/processes and was a step/price higher.
Concord/VIP also made craft fabric items like panels and seasonal prints and the quality of those fabrics maybe isn't up to that used in the Kessler lines. As always, judge each piece on an individual basis.