RAP,
Microdol is like the anti-pryo! to provide very fine grain it disolves the edges of the physical silver in the film, and costs you a stop of film speed. Makes any film appear less sharp than it could be. Pyro has the opposite effect, that is, it makes the film appear sharper than is possible with a conventional developer. If I wanted less grain, I'd use a finer grain film.

What format are you using? In 35mm tri-x, I like HC-110 or D76 1:1. in medium or large format, I would use TXP. I'm starting to like Pyrocat HD. In my first comparisons with Rollopyro, the pyrocat is at least as good, with no uneven staining issues. My contact print times for TXP are about half those of Rollopyro.
Tom