Whenever new hardware launches, whatever it is, there are problems. The PS Vita is new hardware, and while I haven't experienced any hardware issues, others have. These are some of them.
According to YouTube videos, there are some machines experiencing lock-ups and freezing. One error appears to occur during the System Update, which then freezes. Another issue seems to be a non-responsive touch screen. It's still early in the hardware's launch cycle, so it's difficult to discern how widespread the issue is. Pro-gamer Kiryu Tsukimiya tweeted that he's soon experienced it.
When the PS Vita freezes, the hardware apparently will not shutdown. A writer at Japanese news site Rocket News experienced that issue during Shin Sangoku Musou Next online play.
When the machine is in its regular operational state, if you press the power button, the Vita should shutdown. If it does not shutdown then, Sony's PS Vita help page said to try the following: keep holding the power button for 20 seconds until the front screen goes dark. Then, press the power button for five seconds to turn it back on. That apparently should work, and according to the Rocket News writer, it powered down his Vita. However, he repeatedly experienced the bug while playing Shin Sangoku Musou Next online.
These aren't the only issues, though. Online, some PS Vita owners are also reporting that they cannot boot up their PS Vitas, even though the handhelds have a full charge. There could be an explanation for this, and Rocket News has a walkthrough, that consists of questions to determine if the PS Vita owner held down the power button long enough or if the handheld is simply in standby mode.
I'd imagine these sort of issues would be handled by the time the Vita launches in the West in Feb. 2012. One of the more worrying issues, however, is the possibility of screen "stains" or "spots" on the OLED display. One Japanese PS Vita owner uploaded photos of his Vita screen, which supposedly shows display screen issues.
Oh, the joys of launching new hardware and being an early adaptor. That's what system updates and hardware upgrades are for -- fixing.
「PSVITA」にフリーズする不具合多発！ その対処方法 [Rocket News]