I initially rated Minbox very poorly, given the long wait time to access the app. However, since my previous review, I have had time to use Minbox on a regular basis and find it very useful for my particular routine. For someone like me, who has little reason to purchase a paid Dropbox account (though I do love Dropbox), Minbox is perfect for sending large video files (500MB+) to coworkers. No issues with upload or download speeds.
I did have an issue with the app crashing when I tried to access the preferences, but I received a response and a fix within 24 hours of my initial message.
The wait was long, and the app still isn't absolutely perfect, but it is certainly much, much better than I initially thought it would be.