Favorite Brand of Oil Paints?

[haikujaguar]

I am experimenting here; several of my books say the paint out of the tube should be usable for some purposes, and the brand I've got (my favorite for gouache, M. Graham), is absolutely not usable straight out of the tube. It's been decades since I've used oils but I don't remember needing to use a medium just to get it on the canvas...!

If you paint with oils, what's your favorite brand? I think some experimentation is in order. :)