It is like Nintendo Gameboy but with colors. Vita was sold at high prices with a poor software catalog and many consider it flopped totally.
A smartphone is much better and, well, smarter choice for portable gaming.
Probably said by someone who hasn't owned a PS Vita? Anyway having owned a high end smart phone playing any AAA titles becomes a challenge. FPS shooters are one of the most difficult with trying to use the onscreen controller and sliding all over the place. With the Vita you get real controls just like a PS3 controller.
Comparing a Nintendo Gameboy with a Vita is also a strange one, sure both are portable consoles but the Gameboy is prehistoric compared to it. It would be better to compare a 2DS or 3DS with the Vita, even then the Nintendo screen is nowhere as good as the Vita.
The Vita also has the ability to be used as a controller for the PS4/PS3.
It also has touch on the rear and front of it so makes for some amazing games, especially using the rear touch pad. Just need to google Little Deviants which is highly addictive and uses the rear touch pad and augmented reality.
The augmented reality is fantastic, once you've played mini golf on your coffee table or played tanks and attack each other you can't stop.
There is a geocaching game I like to play on it uses both GPS and augmented reality to capture items/monsters etc is a lot of fun. Plus people nearby can join in on the hunt or you can invite friends to join in.
Anyway I love the Lemmings game on it. But there will always be haters, mostly people who have never owned or tried a device.