PSN PLUS IS NOT CLOUD
This game does not use the online storage that you get with PSN+ it uses the 1MB online saves that all games get reguardless of PSN+ for example if you delete your KZ2 save your online rank remains intact cos that is stored online in that games 1MB title storage.
So YES Ruin save will be transferable for all users as the save will be saved in Title storage, not PSN+ online storage.
The online storage that PSN+ offers is not really cloud storage, cloud implies you can save and load from that space and you simply cant, its just an online backup, that you must manually copy the save from if you ever want to load from them.
SOURCE: http://deltagamer.com/12058/sony-ps-vita-can-be-used-as-a-controller-for-ps3
"We have a system called Title User Storage, which allows 1MB of data on our servers for game, and that can be accessed on both platforms; you can access that same data.
You can save your game on PS3, go over to Vita, pull that data back and swap it between them, so you can play a game at home, take it on the train and continue."
