Ok, I measured my fatty and slim for a size comparison. I have noticed that in pictures the slim appears to be larger than it truly is. But anyways here goes
Slim PS2=>L-9" W-6" H-1"
Fatty PS2=>L-12" W-7" H-3"
And like Gina said, it probably weighs about half of what the original does. My only gripes are the tiny buttons, and no true on/off switch.
The on/off switch doesn't bother me, it stays cold when on standby so it's not using any electricity but I guess it's storing some in it so when it starts up it starts fast and doesn't have to warm up.
Yea, I doubt it's harmful to leave it plugged in. I dont know though, I just have this thing about unplugging it. I probably wouldnt be able to sleep knowing it was on, I would have a permanent image of that devilishly red light seared into my brain.