The good The new Vita Slim charges with any Micro-USB cable, is thinner and lighter, has improved battery life, and works nicely as a PS4 accessory for local game streaming. The game library's gotten really good, too, including freebies for PS Plus subscribers.
The bad Expensive proprietary memory cards are necessary and annoying; new LCD display is less vivid than the original Vita's OLED display; the lack of rumble and extra buttons means some remote-play PS4 games translate awkwardly.
The bottom line Two years in, the PlayStation Vita has come of age and become a refined piece of hardware and an excellent place to play a lot of games. You don't need one, but it's really fun and worth its price