When I run the Speedtest app on my device, I get between 300-700mbps download speeds. However, when I have my Channels app pointed at my DVR over the local network (configured "At Home") and I want to download a show for local playback later, The Channels app reports a ~13mpbs download speed.
(My DVR is a Synology DS220+ connected to a gigabit switch and I've tried the app connected via ethernet and 5GHz wifi with the same low download speed.)