I use both of them. Happy with both brands, pretty much interchangeable and identical. But then you would expect them to be seeing as they are both made in the same factory. (As are P3, RailMatch, and I think the current crop of Humbrol acrylics) (Although I might possibly slightly prefer Foundry as they have a bigger range of colours)
I had no idea 12ml CDA and 20ml Foundry paints were made in the same factory…
CDA are my go to range*, as I started off with Citadel, and though I do like Foundry, their price hikes on paints and increase in shipping, has dissuaded me from ordering more than once or twice a year. Haven’t purchased CDA in over a year, so no idea about the decline in quality – has anyone contacted Black Hat?
*mail ordered, as the only brands available locally are from GW.