How should they value your time spent in the game? I mean even if you could only play say 4 hours on the weekend that's 16 hours a month. Is 1 dollar per hour too much? What if you also catch some time at the end of a workday?  That drops the cost per hour to well below 1 dollar.

15 dollars a month is fairly reasonable, as a pay per use method would likely end up costing more than you want especially if you don't play the same number of hours every month.

I liked the concept of Watch Dogs... I just don't think the mobile app aspect of the game is going to work if the game doesn't sell well.

Sony fans pray that they don't. That's the only ammo they have, considering there's no exclusives.Karnage108

Well Sony is being smart. 5usd/month for PSN+ which is the same for XBL Gold.  They've already won the price point battle, and they aren't including stupid features that nobody wants or needs.  So as they win gamers away from xbox they'll already be used to paying a fee for online services and won't even notice a difference.