I have a 4 way secondary to for my 4 tap keezer. At least 90% of the time they're all set to the same pressure.
It is nice to pump it up for the first day of a force carb, drop down a few PSI for stouts and english beers, or go up a few for wheats and belgians. However, I find that I don't very often do that.
That said, if I were starting over, I'd probably hunt for a deal on a multi-pressure secondary regulator again. Having two pressures and some manifolds would work just as well for me, but I'm not sure if that would really save any money (and more connections = more potential for leaks).