I use Foundry paints almost exclusively, and I really like them, the reds work for me I usually use a base coat of Wine Red shade, built up with the 3 Bright Reds, and finally a glaze of Scarlet highlight, I used this method on the Egyptian Major by Gringo 40, the Red is a lot brighter in reality,tomorrow will see if I can get a better photo so you can see the actual color achieved.

I agree that the Deep Blue lacks contrast, and I also find that some colors (Rawhide, still probaly my most used pot paint) have to big a contrast so I have darkened down the highlight pot. I also think the range of Greens, Browns and other muted tones is excellent.
Apart from Foundry I use GW metallics and washes, particularly Devlan Mud wash, I wish they would sell it by the bucketful

I also use their Blacks and Whites as they are easier to get hold of.