iT500 4+

Do yourself a favour and go with Hive or Nest. This system is simply appalling and is so glitchy and temperamental when it does work.
Often my thermostat is offline when I know it's connected just fine, then I have to turn the Ethernet transmitter off and on again to reset. Half the time it won't do what I ask even though it says it has, so the heating won't turn off or on as I want. Then there are the error and timeout messages.
Once or twice I've also come home to the hearing being on in the middle of the summer when I've turned the system to 'off'.
Even if all that was fixed the app is still clunky and not intuitive to use.
How I wish I went for one of the others!

I really like the functionality that the app provides. But have a fear of increasing my heating, for a cheeky heating boost, without checking that there is another timer programme set so that it'll turn off soon.

The addition of a, simple, boost button would be amazing. And a pretty straight forward, technically, too. If you wanted to wow me you could make that boost button have a few set table boosts say...15, 30, 45, 60 mins, or even heat for ... and then a "drop down" wheel for the number of minutes.

I often only want to take the chill off before I head robbed. But it would be a m a zing

I’ve had the it500 installed for years and it has worked without any major issues, apart from an annoying update to the thermostat that made temperature changes in increments of 0.1 instead of 0.5, meaning loads of annoyance MG tapping to change the temperature. The app has been reasonably reliable up until now, but something changed in 2020 that has just made it so flakey to the point that you have to repeat manual changes because the app times out or nothing happens. I’m not sure who is doing Salus’ development and evaluation, but they don’t appear to be doing it well.
I’ve had enough, and will be changing the Salus unit to something else.