I own the pre-cursor to the Cuisinart (the DeLonghi 7 Qt), as well as a few KitchenAids and a genuine Hobart 5 Qt N-50. Hobart originally made the 4.5 and 5 quart mixers, but sold its KitchenAid division to Whirlpool about 20 years ago, and Whirlpool has been making modifications ever since - some good and some not so good.
You also may want to keep in mind that the current Cuisinart line started out life as the Kenwood brand mixer (originally sold in UK), was then sold in the US under the Rival brand for a while, then under the Delonghi brand, and now, with a very modest redesign (more plastic) the Cuisinart brand. DeLonghi was responsible for ramping up the wattage of the mixer to 800 watts for the 5 qt. and a Frankensteinian 1000 watts for the 7 quart model - all as an advertising gimmic. While the lights do temporararily dim when I turn on my 1000 watt mixer (as in a vintage prison movie), this is because of its wasteful draw of electricity, and not because it is delivering more power at the beater, as you will see in my explanation below. Reviews have not been stellar for the Cuisinart - for either sized model. Depending upon how well this unit sells for Cuisinart, you may find it popping up under yet another brand name, with or without slight modifications, or it may just go away, leaving you scrounging for accessories (those that are available now are few and far between) and repair parts as well. So, this is not a mixer for the person to whom it is important for the brand to persist for years to come.
KitchenAid began putting plastic gearbox covers (the housing that holds the gears together and keeps them properly meshed as they turn) in their mixers some years ago, which has lead to durability problems and millions of complaints about them. KitchenAid has promised to revert to a metal gearbox cover in future, but I find it very difficult to trust a company that has cheapened an appliance advertised and sold as being of "heirloom" quality and durability. KitchenAid has "retaliated" by flooding the consumer market with a confusing array of mixers (in 1985, they had two models, the 4.5 qt head lift up and the 5 qt crank up). From making a few simple models well, they now have opted to make many models poorly, or so it seems.
Either brand should be fine for the non-breadmaker who does light chores like whipping cream (high speed but low torque requirements). However, if one makes bread, one will find the Cuisinart skipping all over the counter (it is light), versus finding the KitchenAid's gears stripped after comparatively few uses. Its not a pretty mixing landscape for home bakers unless one is willing to shell out the money for the Hobart N-50, which is the granddaddy of them all, and has only 3 speeds. (The Viking mixer has also fallen into disrepute due to reliability problems, and so fails to offer any relief on the reliability front).
My suggestion would be to phone KitchenAid and inquire if they have gotten around to correcting the gearbox cover problem of the past few years. The rep will invariably tell you that their mixers are made with all steel gears, but this is not the issue - if the gearbox cover cracks from the heat, those steel gears misalign and basically self-destruct, leaving you with pieces of steel gears inside your machine after you've heard some terribly expensive-sounding gnashing. The question is "what is the gearbox cover made of - plastic, or metal"? If KitchenAid can assure you that it has returned to the use of a metal gearbox cover, I would go for the KitchenAid. Also, with KitchenAid, you'll always be assured of an adequate variety of accessories because the brand is unlikely to go away.
Regarding your inquiry about wattage, wattage has NO correlation with power. Wattage is the measurement of how much power the mixer motor consumes. And the notion that the more watttage one feeds into a motor, the more power it will put out out is completely false. A poor quality motor that is inefficient will consume lots of electricity (wattage), but not give it back to the user in the form of task power. For example, my industrial Hobart N-5 purrs along with a tremendous amount of task power, all the time using only 300 watts of power. My Delonghi (1000 watts) generates more heat and noise, but is the less powerful of the two, though each is adequate for light chores. Much of my pleasure in cooking comes from using appliances and implements that are finely and adequately engineered, as opposed to being on the ragged edge of their engineering, ready, in this case, at the sight of heavy cookie dough, to require a trip to the repair shop, requisite with all the awfully annoying and time consuming phone conversations with reps to get the thing fixed.....Which is why I bought the Hobart N-50 and abide by its 3 speed limitation and high (~$1000) price tag.
Hope this helps.
Bob