I bought this to replace my Braun hand blender which had started to make worrying "fizzy" noise in the handle part - not good for an electrical appliance! I have to say that there are definite pros and cons to the Kenwood system.
I liked the idea of having a minature chopping bowl to save getting out my big food processor to make a small amount of breadcrumbs or whatever, but I've yet to use it so can't comment on that.
The hand blender stick appears more powerful than the cheaper Braun and makes my breakfast smoothie smoother. But this means it is a bit more difficult to control. Also, the Kenwood stick has a different design at the bottom which makes it splashier than the Braun - more difficult to blend small quantities without getting it all over you. But I expect the Kenwood would be better for blending a huge pan of soup.
Another whinge - WHY OH WHY can't manufacturers design things better to go in the dishwasher?! This Kenwood chopping bowl and beaker have a stupid base which ends up full of water at the end of the cycle. Also the top bit of the chopping bowl and the holder for the whisk are not dishwashable.
So - for small amounts get the cheap and cheerful Braun, for bigger jobs and if you really want the small chopping bowl get this one.