I hope you won't mind if I add a thought TheHowser, even though I don't have a KitchenAid.
Kenwood have quite a large range of mixers, which is reflected in the build, and in the price - so if you are comparing KA with Kenwood, I would suggest comparing like with like in terms of price range, build quality, and individual appliance specification.
The Kenwood Major range, which includes the more powerful and quieter mixers, starts at around £300.
Kenwood also include in the box the option to take out an insurance on the machines for on-site repair for a period of 5 years - at a very reasonable charge considering the average call-out fee for home repair on a domestic appliance these days. It also covers accidental damage.
Kenwood also have a very impressive service back-up department and you can still get parts for machines that go back some years. You can also pick up the wide range of accessories on ebay (such as the mincer attachment, etc, for a few pounds - absolute snips!).
I'm not trying to persuade you in either direction, because I think KA and Kenwood are both very good machines.
I have no connection with Kenwood either - other than owning one of their mixers.
KA have a trendy image because people like Nigella and James Martin use them on screen - which to be honest is not something that particularly influences me one way or another. But if I was looking for guidance from celeb chef endorsement, I would take account of the fact that Heston Blumenthal uses a Kenwood on screen, and if anyone knows what makes for a good mixer in practice when cooking, and in terms of build quality, it's him.
Kitchen Aid are very well made machines, and whichever you choose, I doubt that you will be disappointed. I just thought having a few extra details about Kenwood might help with your decision-making.
Good luck with your purchase, and all the best.