I just got my 4210 today (hurrah!) and have spent the last couple of hours getting it set up and tweaked, running it with the AC power plugged in (which from what I've read produces more heat than running it just on battery). I'd been quite worried about heat issues, and have now concluded in relief that it's not really a problem--no worse than with any other laptop I've handled. There is one small hot spot (top left, I think, when it's in tablet mode) but the rest of the computer is warm without being significantly uncomfortable to hold, though I wouldn't want to rest it directly on my lap for any extended period. I am overall very happy with the computer--the speed and the quality of the display seem really excellent to me.