Exterior heat is not noticeable. It is a very well insulated unit. I smoked a turkey breast for this last TG and it was the best turkey I have ever had. I got the instructions from http://www.smoking-meat.com/october-2010-smoked-bone-in-turkey-breast.html. I only brined the breast -- no rub. Then wrapped it in foil and a couple of towels for insulation for about 35 minutes. It was, by far, the most moist turkey I have ever had. Hope this helps.
The maximum heat (per the instruction manual) is 275 degrees. I always smoke my meats at 230. The temperature does not vary by more than 5 +/- degrees from my setting. I have excellent results using this smoker.
The Cabinet itself does not get hot, however, the vent on top does produce heat and smoke. I have not really paid that much attention to the cabinet because the unit is outside when smoking. FYI, great smoker.
The outside does not get hot; you can touch the outside. There is a vent @ the top where smoke comes out. On another note, we have had our unit since June. When using to smoke a turkey for Thanksgiving the temperature gauge is reading 400 degrees all the time; when set to only 250 degrees. Seems to be malfunctioning already.