Mine got hot once only, when i was downloadingwith wifi many videos from youtube, but i think its the same with all smartphones when u push it to heavy downloads.

My N9 got slow only once when i tried around 20/25 apps same time to test multitasking limits, but it wasnt hot. It gets slow also when i go online for facebook chat in my contact apps, coz i have 1600 facebook contacts to check and deal with, but it doesnt get hot.

But i have to say that the N9 is very very sensitive to few changes u can make in the settings, a permanent 3g, or a double network then te phone constantly changes it, background internet connection or not, clear wallpaper, 60% of light or more for the screen, and the battery gives you few hours using it, maybe 6. Its a problem for me i'm a bit deceived about that. I dunno if we compare both systems but my N8 with symbian anna after one year has a lot more battery life, with permanent 3g, high lightning for screen, automatic checks for emails and a lot of web browsing...

Thats the main issue for me, stay on 2g, do not update every 30mn automatic feeds, or your battery will be really poor, like you have a sport car but can't speed with it.

Extensive 3G traffic makes the antenna go hot. Otherwise my N9 doesn't get hot at all, even with more than 10 apps open at a time.

i think i got a defective unit again.. this is frustrating..

It's good to read this, because my N9 indeed didn't/doesn't get hot when using WiFi and multitasking, but when I started to use 3G (mail, RSS, Facebook, Firefox, ...) I noticed it got warm. Not HOT, just warm, front and back.