I agree, Studio 11 is quite stable. As far as additional features you would get with "Ultimate" version - a) sound soap, b) Moving Picture, e) Vitascene filter effects and transitions.

Haven't used any of them much, but if the difference in price between Plus and Ultimate is minimal, might as well get the Ultimate.

MOving to a higher end editor is a) pricey and b) bigger learning curve - fine if you have the time and inclination.