I had some issues, at first, getting the new Downcast Mac App to sync with my iOS device using iCloud. The problem wasn’t with Downcast, it was with iCloud.
I had to navigate to Settings > iCloud > Documents & Data and check the option to Use Cellular Data. This enabled syncing when you are not on Wifi. I, personally, don’t use documents in iCloud, so I enabled it.
I will publish a review at a later point, but so far so good!