Squishy
Queen Clown Slayer
Not a professional, but just want to feel included LOL 
Having never used a '+' I don't know how much effect the internal mac valve has - but I'm not sure it makes a difference where the air is regulated, it's the amount of air used that affects how the paint behaves. But Iwata are the experts, and I am no scientist.
All I know is I prefer the cm-c, because I like the larger cup size, and I prefer the external valve. It actually helps make my grip more comfortable, plus it is underneath at not in the way on the front of the brush. Plus I can also use it on my other brush. And as mentioned, if anything went wrong with it, I could just swap it out, or just regulate direct from the compressor, and still use the brush. And (although it was a gift, it was the one I was mooning over, as it was the one I was likely to be able to afford one day) the price difference was a big factor too.
Having never used a '+' I don't know how much effect the internal mac valve has - but I'm not sure it makes a difference where the air is regulated, it's the amount of air used that affects how the paint behaves. But Iwata are the experts, and I am no scientist.
All I know is I prefer the cm-c, because I like the larger cup size, and I prefer the external valve. It actually helps make my grip more comfortable, plus it is underneath at not in the way on the front of the brush. Plus I can also use it on my other brush. And as mentioned, if anything went wrong with it, I could just swap it out, or just regulate direct from the compressor, and still use the brush. And (although it was a gift, it was the one I was mooning over, as it was the one I was likely to be able to afford one day) the price difference was a big factor too.
