I find Gamblin's flake white replacement to be very buttery and I like the way it flows on my brush. It blends well with my other paints too.
It is very dense and covers well without "sinking in" (so far) as much as the Titanium White Alkyd that I have been using lately. I am finding that it is faster and easier to build light with this particular paint. And it drys relatively quickly too.
I will not use leaded paint any more and this really does seem like the substitute I have been looking for....