This is a very personal matter but here are my views for what they are worth. The Kenwood Chef I have had for over 25 years is still going and is very reliable but about six months ago I needed to spread the risk and buy another mixer. Looked at the Kitchen Aid but, frankly, it’s pricey and I am not a fan of the American retro look. The Chef or its modern equivalent was also rather expensive and there was a deal on the K mix so K mix it was.
It has a larger bowl than the chef and will handle 1300g flour which will make about 2.2kg dough so good for 4-5 loaves. If you are serious about bread and using the mixer a lot, make sure the mixer has metal gears; much more robust than plastic. Apart from a minor problem engaging the dough hook and the danger of dropping the arm because there is no resistance, the K mix works well and looks good.
Other mixers are available.