I have 2 KA stand mixers. K45SSWH and a KM25GOXWH (Classic and Commercial). I know that there is better mixers on the market. But I have just under $100 in both, you can't beat that. The Classic was given to me with a stripped gear, which I repaired for just under $20. The Commercial, I bought at a thrift store for $20 without a bowl and paddles. I picked up all the missing pieces from yard sales and flea markets. The most expensive part for the Commercial (the bowl), I got as a present. I know the limited power on the Classic, so I treat it accordingly.
The Commercial will do anything I have mixed, and I do a lot of pasta which is hard on a mixer (there is no way to over-knead pasta dough, the more the better). When it seems like it is laboring hard with the spiral dough hook, I just lower the bowl a little.
The Classic is a 1999 model, and the Commercial is a 2005 model. I believe them to be built before KA started using outsourced, inferior parts (granted still not as bulletproof as the Hobart built ones).
My elderly mother has a late model, 600 model, I think. And it makes more noise than a hay bailer. Both of mine working at the same time (and I've used them both on several occasions), don't make as much noise as hers.