Re: F.A.O. Azure
I have the chalky ones Tabby.
I've found them not so good for fine detail but terrific for blending and shading and achieving a soft effect.
They are messy .... imagine a fine dust floating and coating your work area, so take care ... that's the down side.
Nor do they take well to too much overworking.
For detail they take pen work or an ink overlay well.
As to paper. Avoid anything too over smooth. I've worked them well on virtually anything else, especially the sketchpads you can now buy of textured watercolour paper.
Pastels are great for blending!