It's a personal choice, I've used both alongside each other with a wide variety of films. My preference is Pyrocat HD, but there's so little in it that I'd be just as happy using Xtol.

So my preference isn't based on the type of film, however if you were taking about Rodinal then I would only use if for slower emulsions. Pyrocat HD is like Rodinal on steroids quite different.

IAn