Agreed that temperature control and flow rate are both more important. But which tankless provides both features better than any other manufacturer does? according to the Center for Energy and the Environment, Noritz wins on both counts. Don't get me wrong, Rinnai is a very good unit, but I still like Noritz better. Navien has made some improvements to their water heaters over time, but they are still nowhere near the Japanese manufactures such as Rinnai, Takagi (now AO Smith), or Noritz. As for me, I will stick with Noritz any day.