Haven't heard much about Sonar plug-ins, but Home Recording magazing did a review of Waves Gold Bundle (which includes the plug-ins included in the Power Pack) in December 2000. To sum up the review by David Darlington:
"The first thing I have to tell you about Waves versus the competition is that Waves sounds better than just about every Mac based plug-in I've worked with (and that says a lot). This is not just my opinion but the consensus of almost every engineer, DAW operator, programmer, and gearhead that I know."