I purchased the 4 Qt 3-in-1 Cook Central Multicooker several weeks ago after much research.  I needed a slow cooker that did a great job of controlling the temperature and I found it!  My pasta sauce was the "test".  It didn't leave black marks around the edges like a competitors product did while only on the "warm" setting.  I am using it so much that I don't even bother to take it off my counter.