PS+ is a great service. All you need to do is just checkout or purchase the games, you don't need to d/l them until you want to play them. If you don't purchase it, and it goes off PS+ then you won't get access to it later.
The 1 GB online storage for the PS3 and a separate 1GB online storage for the Vita is also nice and works well.
I got a Black Ops Vita Bundle on sale to get a Vita, and haven't bought a game yet. I have Black Ops on card, and bought a 16GB mem card for which I have Gravity Rush, Uncharted, Retro City Rampage, Foosball, FF Tactics, Ninja Gaiden, Wipeout 2048, Jet Set Radio, and Mutant Blobs attack from PS+ membership. There were a couple others, but I've already dumped them. Then, I carried over Killzone Liberation PSP and Front Mission 3 PS1 Classic onto my Vita from my old PSP days. So, I have a great variety of games on it.
And...that's just my Vita. Don't get me started on the massive list of PS+ games on my PS3.