Had a 5-year old Oral B with a Bluetooth device that attached to mirror and showed which brushing mode was selected and how long the teeth were being brushed. Decided to give the new IO model a try, especially at the reduced model 5 price drop. Doesn’t use the older brush’s cleaning brushes, but after using the IO, found there is no comparison to the older model. Brush heads are larger, but fit tooth surfaces better. IO has lights built in that indicate if you are brushing with enough or too much pressure, and the brush vibrates every 15 seconds to tell you to switch to a new quadrant. But only on sale!!