A lot has been made about how much hotter the new iPad runs than its predecessors. Overall, the blame has been placed on the much much larger battery found in the device, as well as the higher-res screen, and the updated processor... so essentially there has been blame placed on everything new about the new iPad. Apple, of course, says that the new iPad is "well within... thermal specifications".
Whether or not the iPad performs within the average user's "thermal specifications" are neither here nor there, but PCWorld has done a little research to compare the average temperature of other popular tablets, and the new iPad beats them all (or loses, if you prefer a cooler tablet). PCWorld found that not only is the new iPad hotter on average than the iPad 2, but it also runs quite a bit hotter than the Asus Transformer Prime (anywhere from 4 to 9 degrees hotter, depending on situation.) The Samsung Galaxy Tab 10.1 LTE was more on par with the new iPad heat output, and even a bit hotter at times, but overall the new iPad was definitely hotter than either Android tablet.
There are indications that a hotter battery can lead to a quicker degradation of the battery
, meaning a shorter overall lifespan for your battery, so even if the actual temperatures don't matter too much to you, there may be other reasons to be wary.