I have Pinnacle Studio 9 Plus and I love it. I am holding off on upgrading to version 10 based on some bugs that need to be worked out. But I love my version 9.
I do not do high-end editing with lengthy clips and fancy effects. I keep it pretty simple. Pinnacle has always worked like a charm for me. I do make sure to use "End it All" to turn off all the bothersome programs running in the background while I use Pinnacle. That seems to keep Pinnacle fairly stable.
