Temperatures, Cooling and Noise
As you can see in the picture below, the keyboard gets pretty toasty when the system is under load and this can cause discomfort during use. With a maximum temperature of 116 degrees Fahrenheit, you're not going to want to type for much more than a couple of minutes. With all temperatures above 90 degrees, the whole thing could be used as a space heater. Fortunately, you're usually not stressing the system heavily when typing, so this shouldn't be too much of an issue.
If you're using it while gaming, the system could reach these temperatures, though it's unlikely you'll be playing any seriously demanding games on the integrated HD 3000 graphics. The backside of the laptop also heats up while being stressed, so it's a good idea to use the system while on a table or cooling pad if you're going to be pushing the CPU.
A maximum temperature of 132 degrees Fahrenheit can certainly cause issues with using a laptop directly on your lap. If the machine is too hot it can cause permanent discoloration of the skin. Due to this, I would recommend only using this system on a solid surface.
The reason for this heat is the slimness of the form-factor. Without the luxury of space, everything has to be slimmed down, including the cooling system. This yields smaller, louder fans which have to push more air across a smaller heatsink area. As a result, when this system is pushed, it gets loud. Even sitting at idle typing this, I can hear the fan running.
During normal use, including writing this review, I never experienced heat near what is seen above. The computer is actually an extremely nice system, despite the heat it can produce. Considering most are buying an Ultrabook to be portable so that they can take it to class for taking notes and other lightweight uses, it really is a good fit.