Let me first explain to you the concept of these little tubes, these dont work like regular lipstick or glosses, you just need a tiny amount of it, you can mix color to create a new one, you can play with different shades to create something new. Its really fun, all you need is a small plate (you can also use the back of your hand), a lip brush and choose the colors you want to work with. Add a couple of colors (add more if you need), a tiny drop will do just good, and mix them together. A new color will be created, then you can apply it on your lips. Again, you just need a tiny amount of product to paint your lips, these are heavily pigmented and stay for hours without changing or fading!!
The only downfall is when it comes to retouching, if even needed. I did it once at a wedding and i looked silly mixing colors on my hand.
I havent tried the Sleek Makeup Pout Paints only the OCC Lip Tars, but it looks like to be less pigmented and less variety in colors.
An idea how the lip tars work on mixing:
You can order OCC Lip Tars from the website, and Sleek Makeup Pout Paint from the website too.