The reason is not the cleaning performance or processing, but the outdated battery technology:
I just can not understand how today still products with this traditional battery technology (NiMH) are produced, which means that the battery (if one can be it not always completely empty) increasingly losing power and by about 2 to 3 is broken years.
For handling, I can say that the Pulsonic Slim is through their thin design really easy and "slim". The pulsations lead initially to a slight tingling (you get used to) and provide pleasant smooth teeth.
I am satisfied with the cleaning power of Pulsonic Slim, I now have my big brother (Braun Oral-B Pulsonic Standard Electric sonic toothbrush (standard model of Pulsonic Series)) ordered that a more powerful Li-Ion battery and even more power at the pulsations has.