Asking What brand of paint is best? is like asking What kind of bear is best? It all depends on the artist, and what we are trying to accomplish. Most artists use more than one brand.
Here are my impressions of some artist grade brands:
QoR – Vivid, very bold. A little goes a long way. The binder is Aquasol which is different than any other brand and can hold more pigment than gum Arabic. The paints flow quickly when dropped wet on wet. It is magical to watch.
DaVinci – Excellent paints, great mixing and transparency. And I love that they come in large tubes. This is probably the most economical of all the artist-grade paints. Love them!
Holbein – Bold. A little goes a long way.
Sennelier and M. Graham – Creamy, made with honey, luminous layering.
Schmincke – These paints layer beautifully, so luscious. Luminous and delicate yet can be bold too.
Winsor & Newton – Translucent, beautiful pigments. And I feel a little like royalty using them. Winsor Red is amazing!
Daniel Smith – Many colors available (268), very convenient for those who do not want to mix colors. They have remarkably interesting mixes of colors, with much granulation. This granulation can make an ordinary painting extraordinary! If you buy any Daniel Smith color, get Moonglow. Just trust me. Seriously. Trust me. Put it on your list.
Here are some other articles on paint: