What Thermann has to say-

From day one, our goal has always been a commitment to deliver the ultimate hot water experience every day. Whether that’s through innovative design and technology to ensure easy installation, or the confidence that when you turn on the hot water tap, that’s exactly what you get. It’s a promise we stand behind with our market-leading warranties and after sales support, because we’ll be with you all the way. fluctuations.

What JR has to say-

We are able to service, repair and/or replace any of you favorite Thermann products. Thermann is a Dux made product off the same assembly line exclusively for Reece plumbing stores. In our experience Dux products have been at the bottom of the reliability scale and we have replaced well over 100 units under the ten year period, and in comparison only a handful of Rheem made products under 10 years old. This could be directly related to the units never being serviced as per their warranty, and lets face it no one services their water heater as per the guidelines. But no one services their Rheem either and they keep going. Their new products might be alot better and more reliable but only time will tell and we believe there are better options for your money at this point in  times.

Would we install one on our own house? -

Short answer is maybe. They do now have decent warranties and if you were looking to move the property on they would be a good option. Also if you were prepared to get the system serviced at the required intervals they could be a valid long term option. But if it was one of our properties they wouldn't be an option.