The funny part that it is normal to have these type of deals about PS Plus. I don't see the reason why the OP is now mentioning the games that you can play temporarily for how much you payed for. It seems like he is trying to screw with us around or something. I mean, he still hasn't changed to topic's name.
Anyway, it is just another game you get with PSN Plus. Oh, guys, about the subscription thing, you have to pay for both.
PS Plus, you get discounts, temporary games, and free themes/avatars to keep. Don't need to pay for it to play with other players online.
XBL, it is a must if you want to play with others through online. You get demos a week early...that was pretty much it. But since they just started to use the promotion, you get one free game to keep forever. But it is most likley to be old games that have been forgotten because of superior sequels. Just a prediction...
Overall, I think this might be a troll topic and you pay for both PS Plus and XBL. XBL, you keep games forever but PS Plus, you get much better games but you can only keep them for however long you payed for PS Plus.
Whew, that was a lot to get off my chest.