This machine is a dream to use. I too had the dilemma of KitchenAid or Kenwood - but the man in John Lewis was heavily biased as he'd worked for Kenwood for over 20 years! This is a solid quality machine and looks great, which is handy as it's left out on my worktop. I bought the cream one, because I refused to pay so much more for black (which I think would require constant cleaning) or an admittedly funky red one which I loved - but now I've got it, I am not at all bothered by the colour - don't be a sucker to clever marketing!
I agree with the issue over creaming butter and sugar and it sticking to the sides. As well as useful suggestions such as warming the bowl, I also make sure I use really soft butter at warm room temperature. It's been a problem for years - my mum had an old Kenwood 40 years ago and she had to scrape the sides way back then! Adjusting the beater per the instructions may also help. Once you start adding the eggs, it sorts itself out.
I do find when it's running fast, I can't hear the doorbell or the phone ring - but when you're cooking and the creative juices are flowing, who wants to be disturbed anyway? Suffice to say, it could be quieter, just as well it's only 500w power or I'd have permanent tinitus. I do highly recommend this mixer it's great value for money and on performance to date, I'm expecting it to last me for many years. I've also become strangely popular among friends and family who are happy to be guinea pigs for all the experiments I've been doing with it.