Hey Greg,
Here's my opinion .... and I stress, this is just an opinion.
To me the small Testor's Bottles are leftover's from days gone by. With so many good quality paints on the market, we as modellers have a great selection to work with. The Testor's line still has a market though, and that's the "mom buying little Johnny his first kit and 4 bottles of paint" market.
Now the Model Master's line of paint is an excellent choice. I've used it in the Acrylic form, though I prefer to use Tamiya Acrylics. The colour selections are great, they take well to thinning, and don't seperate from the pigments anywhere near as bad as the old Testor's line.
Just my
Happy Modelling and God Bless
Robert