Actually, DBoost isn't snake oil--my experience has been that it does what it says it does--it speeds up the frontmost application. This might not be as noticeable, if at all, on a G4, but on my Blue & White G3, it does make a difference. Not a huge difference, but the improvement is nice. I've been using it almost since it was released, and it's been doing its job well for me.

It's fine to theorize and say that using the renice command could cause trouble, but that's not backed up by any citations. Yes, renice is there for a reason, and DBoost makes use of it--the reason renice exists is to be used.

As for Zo-1's problem with his Powerbook G4 getting messed up after installing DBoost--the most likely explanation is coincidence. Computers get messed up. It happens. Just because it didn't get messed up when he tried other renicers, doesn't automatically mean DBoost caused the trouble. It's true, you need to consider the last installed thing as the possible cause of trouble that follows, but you don't want to depend too heavily on that concept--I've been fooled many times before.