I have many thousands of mac users at my organization. We recommend Fusion.
They have been responsive, and have been working on the issue. It was introduced by Apple in 10.8.2.
Maybe 10.8.3 will fix it, but 10.8.3 has had 12 builds since late last year, and still hasn't been released. There's a lot of folks over at MacRumors wondering about the delay.
http://www.macrumors.com/2013/03/05/apple-seeds-build-12d76-of-os-x-beta-10-8-3-to-developers/