What I am not sure about is how the processing power/speed effects the speed or "snappiness" of the UI (something that has always been a slight annoyance to me...no customer complaints though), not only on the navigator/TS UI, but the mobile apps as well (which will be effected more so probably by the mobile device processing). I realize C4 says the 800 has 4x the processing power as the 250. But does that equate to "faster" or just "more stuff"?

In my case, we are talking a single zone of AV with on screen navigator, a possibility of adding a second A/V zone without on screen navigator, 4-6 SONOS zones...(or HEOS), lighting control of 20 or less loads. A single in-wall TS, 1 single tstat. Future possibilities are 1 or 2 IP cameras, irrigation control, security integration, and garage door control. Still well within the realm of a single HC250 I think. The question is whether an 800 will make a noticeable difference in regards to the speed of the navigators.

The cost is double. I do not expect the performance to be double, but if it were 15 or 20% faster, I would probably lean towards the 800, although I foresee new hardware again within the next 3 years, and upgrading is always in the forecast anyway. So HC250 it might be for now.