I am not an owner of either, but have worked on the Wesumat and watched a Sonny crew install one of their new machines. Here's what I see on both. The Wesumat does a nice job washing. The parts for it can be very expensive. The ones I've seen have a painted steel frame, not good for a car wash. It can take 7 minutes for a wash. The Sonny machine was fun to watch being installed. I was doing another job at the site. It took four people three weeks to install. The two factory people were on the phone many, many times every day to tech support/engineering. When they finally got it to wash, they realized they had installed the wrong umbilical support. The side brush was tearing itself apart on it. And for some god foresaken reason, it has eleven chemicals online for it. Eleven. My guess is that they are still on the steep side of the learning curve. I would also check out Magic Wands new friction rollover. It will wash a car in about 90 seconds, and do it well. Yes, I do sell them, but that's because they make machines that are easy to work on and operate.