2140 vs 2940
Hi, I own the 2140. My understanding is that ATC on the 2140 regulates the warm and cold settings. If you select "hot", you get tank-temperature hot water without adjustment by the machine. On "warm" and "cold" it mixes both intakes. The latter is useful if you have very cold ground water (i.e. in winter), then it mixes in some hot water to make "cold" but not "ice cold" water!
Given that I'm in California, where the cold water isn't THAT cold, and my washer is adjacent to my water heater, ATC isn't really an issue.
The only other feature that the 2940 has over the 2140 is variable delay wash control. On the 2140, you can choose eight hour delay or no delay (it's either on or off). On the 2940, it's a variable 2-12 hour delay. I didn't see the point of delay wash at first, since my washer is in the garage and noise is not a factor. However, sometimes it's nice to set up a load to wash a load an hour before you return home or before you wake up. Particularly since clothes spun by this washer will often dry in 30-45 minutes. In some areas, electricity rates are lower in the middle of the night, so people can take advantage of off-peak pricing too.
I use delay wash several times a week and it would have been nice to have a variable delay. At the time I made my purchase, I did not think that the $70 price gap at that time justified the extra features, so I bought the 2140. In addition, I was buying a dryer and the 2940's matching dryer was more expensive than the windowless dryer that matches the 2140. So I was looking at a $150 price hike. I went with the 2140 and its windowless dryer (the styling of the control panel is identical, though only one machine has a window). Today, however, you can usually find both machines at the same price, and under today's pricing I would go for the 2940.
The machine has given excellent service for 15 months of ownership. It will accomodate king-sized comforters. The dryer is 5.7 cu ft, smaller than the largest dryers, but by sticking with 5.7 cu ft, they kept the footprint small enough to allow stacked configuration, which is what I did with my machines. This means I have to remove a king size comforter once to turn it inside out in the middle of drying. A minor inconvenience.
One caution with the 2140: there are no drain holes in the gasket crease at six o'clock, so be sure to wipe out any water (usually a few ounces) with a sock or towel at the end of each washday. And keep the door ajar, to avoid any mold build up (leaving the door ajar is a good idea with ANY front loader).