Review (4/5): Good upgrade over the Oral B 1000 if you need the features
We have owned different Oral B power toothbrushes over the years with the latest being the 1000. I have no complaints with the 1000 it works.
When determining if one should purchase the 4000 or the 1000, one needs to look at the additional features the 4000 provides.
If you have sensitive gums then you will need to purchase the 4000, there is a gentle mode. Additionally, I would not recommend purchasing the floss action heads if you have sensitive gums.
While there is an in handle display in the 4000, it is not a digital display. It is a light next to the feature you are currently selecting
I do not see any difference when using the polishing mode in the 4000, however, I do not have stains to determine if the feature works.
The one annoyance for me with the 4000 is that I accidentally change the mode instead of turning off the brush from time to time because the button are close enough to do this.
While I recommend the Oral B 4000, I would suggest using the 1000 if you do not have sensitive or stained teeth.