I have been using Channels exclusively for TVE for a while-- and I just got a HDHR-US. Integration with Channels works great.
I notice that if someone else is using the hdhr, other clients (firetv) get a generic "Playback Failed" message on the screen.
Can you add more information to that?
I have the "Tuner sharing" enabled on all clients, so the feed should be going through the dvr server---
It'd be nice if the screen said something like "No Tuners available-- Channel 3.1 being watched by Joe's FireTV at 192.168.0.2".
It'd also be nice if that same information was displayed in the Activity section of Settings page.
EDIT: This would work really nicely with the option to kick a remote user from watching. For example, a remote firetv could be playing a channel using my HDHR but the TV is actually off-- it'd be nice if I could scroll through each watcher and choose to stop their stream so that I can take the tuner.