I would definitely say go with Premiere. Pinnacle was the first editing program I got and it never really worked properly for me. It ran really slowly on my old computer, ate all the memory and had to shut down constantly. If there wasn't enough memory to render something, it would stop halfway through the rendering process. It would just stop. And even when I got my new computer that has tons of RAM and put the program on it, Pinnacle still didn't run very well. The scene selection feature Studio 7 has is a major problem if you're using whole anime episodes, because it takes a long, long time for it to detect all the scenes.
Premiere is much much better, it allows you to be much more accurate to where you cut your scenes, and it has a wide variety of effects while Pinnacle has a few different transitions and that's about it. Plus Premiere is the only thing I know of that can use the avisynth plug-in, which is very useful when it comes to editing DVD footage. Premiere also seemed to export in higher quality.
Pinnacle was a very frustrating program for me, and had very limited abilities. But with Premiere the sky was the limit, and I would definitely say go with Premiere even though it takes a long time to figure out how to work it properly. But that's what the manual is for I guess