I bought this to use with a new combi boiler that delivers 15 litres a minute. It is superb. The shower is powerful, the temperature barely moves when other taps are turned on, and it looks great. Another plus is that because of the extra risers that fit between the bath and the tap, there is no need to scrabble under the bath ever again to remove it, just detach from the risers - quick and easy.
Slight downsides are that you can only get cold water by turning the thermostat right down, not so quick as a normal mixer tap. However if you always use hot just turn on and get just-right water every time. Also the angle of the flow control might make it difficult for someone older with weak hands, you can't grip it quite the same as a normal tap and there's no lever.
But in operation - perfect. I'm very pleased.