Nothing much to add, more to confirm. I see Pina as being most useful when you are starting to collect lower end Murano, but it doesn't lead you to anywhere near an understanding of Murano, or the techniques. The Heiremans and Mentasti explain Murano style and techniques with illustrations from high end glass, but you can see those same techniques in lower end pieces.
Having shown my preference, I have to add that, rather than make a choice, I'd buy all three, or at least Heiremans and Pina (and then buy Mentasti a week later).
David