I really like the idea of PRCs as they can accomplish things that basic multiclassing cannot. Specifically, they make very good ways to differentiate different organizations, cults, or special niche endeavors not possible with the basic class mechanics.
That being said, I am also a big fan of Base Classes, including additions of new Base Classes. Basically, if a particular role/profession/concept can be envisioned to work from character origins all the way to the theoretical end of a character's career, then a base class ought to be available for that role. If the particular endeavor is more of a sideline to the basic role, or something that is more organizationally based, then a PRC is more appropriate.
So I use both, but to answer the poll, I use PRCs some.