Nope, no freezing to report. My Vita has been on since I got on Friday. I just leave it plugged-in in sleep mode.
I wouldnt leave it plugged in All the time, drain the battery from time to time, or your battery will die forever..
I unplug it once the battery is full. I'm was just saying that I don't shut it off overnight. I leave it in sleep mode, but I plug it in.
I don't think thats good for it, imo. ._.
If it were harmful, it wouldn't let you do it. There's nothing wrong with leaving it in sleep mode and never turning it off. Just like there is nothing wrong with never turning a computer off and always putting it to sleep when it's not in use.
Right now, my Vita is plugged in while in sleep mode. I actually left Uncharted running while it is in sleep mode.
The Vita's multitasking system is pretty impressive. If only we could run the web browser at the same time as a game.