Overall, Gemini does what it is intended to do and efficiently scans folders and notifies you of the duplicates. In order to use the program effectively you should be careful when choosing which duplicate files to remove as it is possible to delete files you actually do need pretty easily. If you take your time reviewing the duplicate file results then chances are you can save yourself some serious disk space in the process. I do recommend this program for someone whose computer is cluttered with unorganized files and folders, but be sure to use caution and do not rush the process.
I cannot recommend this application in it's current state as it will cause you more frustration than it will satisfaction in almost all cases. I don't know of any alternative applications that have similar features to Filmic Pro so for now I would just suggest sticking to the native iOS video application until the stability is vastly improved or a better competitor comes along.