I had my new Viessmann Vitodens 100-W boiler fitted in August 2019 so it's still a bit to early to review the performance of the actual boiler. But I would like to give feedback on the handset control system Vitotrol 100. I think that it's far to complicated for a 'normal' person to operate and I've already had to have the heating engineer back to help me set up the heating programs and the explain again the overall day to day adjustments that I may require. He was here a long time as even he had issues with the programming. Why do you have to make these so complicated? I was advised by the engineer that Honeywell does an alternative controller that is a far more 'basic' controller that may suit my needs more! It's crazy that I've now spent +£3000 on a new boiler and that it's too complicated to operate and I may have to spend an extra £100 on a new controller to get the best out of my new boiler. If I'd know that the controls are so complicated before my purchase, I think that I would have bought a Glowworm boiler instead, whose controls are far more user friendly.