I blogged about my heart wrenching mixer decision (KitchenAid vs Viking) here, and eventually decided on the Viking 5 Qt model.
I chose the grey colour, which is a fairly dark gunmetal colour. I don't know why they call it "stainless grey" because it doesn't resemble stainless steel at all and the bits that are stainless steel are common among all the colours.
I was using a KitchenAid Heavy Duty before this and I have to admit that the Viking is far superior. Rather than a bowl lift, there is a tilt head and the bowl clamps in very securely. One of the things I really didn't like about the KA was the way the bowl sat on the brackets. The handle of the Viking bowl is also very ergonomic.
Probably the most notable difference with the Viking is the shape of the tools. The paddle isn't flat (it's slightly twisted) and the dough hook is entirely different to the KA one. One presumes this is to mix the contents more thoroughly. They twist in very easily. So easily that we wondered if they were actually in!
So far I have tested the beast out with a few things: a double batch of Banana Bread (perfect), Peanut Butter Cookies (also perfect, plus I didn't even soften the butter - I just threw it in cold and it creamed it perfectly!), mashed potatoes (my first time using a mixer for this - also great), cupcakes and buttercream (perfect!) egg whites (perfect, easy though not as fast as I had anticipated) and a couple of 2 loaf batches of bread (bread flour and ww flour totalling 8 cups). The motor definitely wasn't strained when kneading the bread, however the tilt head popped up a couple of times which is apparently a failsafe to preven the gears from stripping if your dough is too stiff. The second batch was a little looser than the first and it wasn't a problem (only did it once).
The funky shaped tools are really good. I think that they incorporate ingredients MUCH more quickly than the KitchenAid. I especially love that you can just chuck them in the dishwasher (they are stainless steel), something which irritated me about the KitchenAid HD (which uses aluminium). There is also a flange at the top of each tool, presumably to prevent batter/crud from getting up into the motor. Seems to work fine. I also find I have to scrape the bowl down less frequently than with the KA.
As for noise, which seems to be a common complaint, I have not been worried by it. It's less noisy than a food processor by far.
Thumbs up, Viking.