No real experience with Rollo Pyro, Steve.

But my experience with Pyrocat-MC, which uses a different developing agent, I think, was definitely in highlight control. You can prevent highlights from blocking up with replenished Xtol if you want. You just have to be careful to not develop too long. But with Pyrocat, you get more separation in the highlights, better contrast, in a negative of the same overall contrast. That's the key. Both developers can develop negatives of identical contrast index. But within the tone scale from the bottom of the shadow details to the top of the highlights, pyro has better local contrast in the highlight spectrum. You may like this, or you may not. This is especially advantageous to you if you photograph scenes of high to extreme contrast and brightness range.
If you photograph in low contrast to medium contrast, that advantage becomes decimated if not completely erased, and something like D76 or HC-110 would constitute a better choice.

Pick your tools based on what you need. Or wrestle the ones you have until it fits anyway. To me, I picked Xtol, because it was the best compromise; in my view it does the least amount of things wrong.

- Thomas