Hey Rory,
From what I have learned so far about it is that H265 will give you a better image at a lower bit rate. However some underlying issues is that is has a higher CPU usage. This higher CPU usage can lead to playback issues on the local DVR depending on the unit's power. For streaming its looks great. Having seen that actually happen the playback get over decode-ability at the DVR monitor we will probably have to use a pc more and more to do playback. If you google H.264 , H.265 you will see what I saw and how to plan for it.