Kitchen Aid 575 watt 'Professional' mixer failure after just 2 months

I was given a 5.5 qt, 575 watt Kitchen Aid "Professional" mixer for Christmas 2012, used it for just over 2 months. I am using again a 300 watt Kitchen Aid mixer, which replaced my first one from the 1980s. I wasn't looking quite yet myself for a new mixer but the 300 watt mixer is showing some wear, and loosening up.

This mixer seemed to struggle from the beginning. I generally make 2 loaves of bread at a time, with a preferment starting on Friday of 125 ml water and 250 g flour, then adding another 125 ml on Saturday and finishing the mixing, cooling in the 'fridge until baking on Sunday. Been doing this for 25 years or so, with relatively little variation.

I don't think this mixer has truly 575 watts of power, with the mixer bowl seeming like it could handle large quantities. I felt it struggled from the moment I started using it, and had taken the 300 watt machine to our cabin. I am back using the 300 watt mixer. The new one simply quit during mixing. The motor sounds like like it is moving inside, but it also sounds like there is something banging around inside it, and the dough hook moves 1/4 or 1/2 a turn and stops, only to start up again.

The mixer was on sale at Costco, and returned it. They didn't even look in the box. I think I will look for another brand of mixer in the future. I see some people have had motors catch fire. Yikes! At least that didn't happen. I'm thinking this was either a lemon or KA is going through some quality control issues. I'd be interested in comments.

7 or 8 years ago I got a Pro 600, to replace the 4 1/2 qt mixer, mainly because I needed something larger - the old KA was still kickin' even though I got it in '76! The new mixer stopped during the first use - I thought maybe I just didn't know something about it, and it had a hidden switch that had tripped. Fortunately, the KA customer service was very helpful - I guess they are ready for things like that? - and sent me a replacement mixer in 2 days, plus a label to mail back the defective one. Most places do not act this quickly for defective items. The second mixer is working fine, KOW, though I had to replace the raw aluminum dough hook and beater with vinyl coated ones. The oxidized coating would come off in the food, unless I polished them frequently - something that I really did not like to do. Dave

Bummer about the mixer. That advertised 575 watts refers to input wattage - has nothing to do with the actual power of the machine. KitchenAid doesn't advertise the actual output wattage. Quoting from Cook's Illustrated:

We did wonder whether statistics listing power meant anything. Only a few mixers list output wattage (horsepower); most list input power (wattage). Output wattage is the amount of power the motor actually produces—which flows out of the motor, moves through the mixer arm, and, ultimately, smacks the ingredients around. Input wattage is simply the power that flows from the electrical outlet into the mixer's motor. What does input wattage tell you about the power of a mixer? Absolutely nothing—it's purely a marketing gimmick

http://www.cooksillustrated.com/equipment/overview.asp?docid=12382

There's been quite a bit written here about mixers; the search bar will take you to lots and lots of opinions.