They were pretty much dead on arrival across the world really, took off a little in Japan but still wasn't great. Sony don't even talk about it anymore. I have no faith in buying one, would probably rather buy a Vita but not even sure about them.
The PlayStation TV can be pretty good if you just want to play a few Vita games, but don't want to buy the more expensive Vita, and prefer a bigger screen to play games.
But, I feel buying a Mini PC like the Intel Compute Stick or Zotac mini PCs, or laptop, and hooking it up to a TV with a HDMI cable would be better for ROMs because PC support more emulators, play flash games like Tetris, Pac-Man, Space invaders, and Pong on PC web browsers like Firefox and Chrome, and you can buy classic console and PC games on Steam, Gog, and other online downloadable games store.
I never picked one of those up. Really haven't heard much about them either, don't seem too popular. I may pick one up soon as it'd be cool to stream my PS4 to different rooms, and play some Vita games.
To be honest it's not a device that I intend to be linking up either, and I'd say that pretty much sums up other peoples attitudes towards it aswell.
I think even Sony themselves have given up promoting the device for now, and I wouldn't be surpassed if it slowly just faded away. While I wouldn't go as far as to say it's been a flop, it's certainly not been a device that Sony can put down as a huge success either.