I have used Pinnacle 8 Studio Plus and upgraded to 9 Studio Plus. It is a good program, rather complicated to use but it certainly has the ability to produce professional quality results.
I recently purchased an upgraded PC with Media center 2005. My problem is editing and authoring DVDs. MS Media center records TV programs in a DVR-MS format which is not currently supported by Pinnacle Studio. I researched the WEB forums and reviews, and called several vendors. As a result I got lots of conflicting answers, but I found that Nero Version 7 includes a program "Nero Vision Express 3" that is capable of importing, editing, and transcoding these DVR-MS files to MPEG for butning to DVD.
While Nero Vision works well for me, it is very "lite" on features and functions compared to Pinnacle. And Pinnacle seems to be much slower in rendering the final output for burning to DVD than Nero. For now I'll keep using Nero in hopes that Pinnacle gets up to speed with handling Media Center file formats.
To summarize, I prefer Pinnacle over Nero because of the extras they provide, but I won't spend the cash to upgrade past Studio Plus 9 until they can handle my needs.
Hope this helps,
John