One thing I noticed that TVHeadEnd does that Emby DVR does not do yet has to do with keeping tuner utilization down when watching multiple subchannels on the same tv stream.
For instance, on TVHeadEnd, when I watch/record something on 12.1 and 12.2 at the same time, it will only use one tuner and split the streams out properly. On Emby, it uses two tuners to do the same, even though both of them are tuning to the exact same frequency. I believe implementing this feature would help reduce the number of recording conflicts seen on people's systems where a tuner isn't available. It should also help with network utilization as there is no need for two duplicate streams just to receive and strip out the ones you want.
Great software though. I am moving from a TVHeadEnd/Plex setup on a computer to Emby on a Synology DS918+. Both setups are/were utilizing HDHomeRuns for the tuners. I am extremely happy with it, so much so that I sprung for the lifetime subscription. This is certainly software worth supporting.