Thanks for your very helpful articles on the Sonicare models. They were really useful for cutting through the fat so to speak. I ended up purchasing the series 3 gum health. Unfortunately I didn't realize that the user can't disable smart timer or quadpacer on this model if desired (others with mode button can disable quad pacer). I also didn't realize that the toothbrush shuts off after two minutes (smarttimer). Not sure if i just missed out on this, or if it needs to be added. Not a huge problem; i may actually need these timers to brush properly for at least two minutes.