That question was answered weeks ago. Mojang said it on their website:
If you own the PS3 version you get the Vita version for free and if you wanna upgrade from PS3 to PS4 is $4.99.
It will support cross-save from PS3 to PSVita and to PS4 but worlds on the PS4 can't be transferred to the PS3/Vita.
Here we go.
I didn't even got a chance to see the video. Damn YouTube.
Well this is not a problem for me since I don't own a PS3, but I've missed a lot of games. So I'll be using this service to play some of the games I've missed (if they are available)on my Vita.
You know what's funny? The fact that Sony has been selling PS1 games for $4.99 - $9.99 for years and while you could pop in a disc in your PS3 and play them for free, ps1 games are available on almost every platform, most of which enable you to download the games for free, yet the ones who chose to pay for the PSOne classics are not complaining. I have never seen anyone complain about how pricey PSOne Classic are despite being "old games". Cause that's what they're sayin...