I felt adobe rush was somewhat underwhelming, but had a really good user interface. I've used LumaFusion for a few years which is getting better and better by the month. One time payment, and also has tweening animation which I've found very hard to find in other video editors.
Tweening animation essentially means you can move the frame of the video or graphic around on the screen. For me, not having that is a deal breaker.
But now that iOS has improved significantly, I sense a lot of video apps are going to improve a lot, and there's rumors that Final Cut Pro is coming to iOS. when it does I'll be on it straight away.