Got one here, for the money I think it is a good idea to have one fitted. First couple of runs complete black sludge. 18 months later every 3 months or so not as much sludge but still a fair amount of 'stuff' collected.
Oil here and I have TADO, really impressed so far. The only slight glitch is the Apple Phone software 'location' doesn't update as often as Android, that's the wife.
Really like TADO and would recommend it
We have got one in our kitchen due to having a large window and stone floor. I am quite happy with it, heat output is good on the low fan setting, you can still hear the fan - nothing ridiculous. I couldn't have it on the high setting all the time but for a burst of heat it is ok to put up with...