The best, but...

...honestly thats not a high bar to meet. Pinnacle is certainly the most feature-rich video editors for iPhone and iPad and even approaches very low-end desktop-class editing. What it really needs though is more than one video track for proper titling and video effects instead of the ridiculous way it handles titling now, not to mention that it cant even play back realtime video when a title is applied, the entire thing bogs right down even on an iPhone 6 Plus. Still, nothing else had as many features or comes as close to desktop-class editing, so its the best we have. It could just stand to be miles better with just a few simple feature additions. Even if they added 3 video tracks (or even titling tracks) to the new pro version I would definitely pay the high $16 cost for it. But as it is theres no way that version is worth that kind of money to me without more desktop-class features like multiple video layers.

Mindfield about Pinnacle Studio - video editing, v5.4.2