This was actually the other day, but I've not been on.
A friend of mine got me PS4 Minecraft as a late birthday present so we could play together. Uploaded my save from PS3 and downloaded to PS4.
Downsides: PS3 game doesn't update along with PS4. Not sure why I expected it to but I'm still a bit disappointed. Also found out that the small world limit on the PS3 doesn't increase if you transfer it to PS4; you have to start from scratch on the PS4 version.
Upsides: I can play it with friends on either console and I can upload gameplay vidyas
which I already had some fun with. And finally, the lag issue I had around my house is no longer a problem, though the pointer - when I open my inventory - doesn't move as quickly as it should.