I'm still using and stratified with its performance. I set it on 45C, it takes around 10 minutes to reach that temp from 28C. 30L water at 45C is enough for one person's bath without mixing cold water. You can set at higher temp upto 80C as per your need. I prefer 45C as no need of mixing and its less likly to damage PPRC green pipes.
I'm using wifi breaker with it to turn it on at predefined schedule or need based, not always on.
I have instant LPG water heater as backup, not recommend as there is no control over temperature, it can effect the PPRC pipe joints and running cost is also more than the electric one.