A good editorial article talking about how the way MS is using the free-to-play mechanics is a bad decision for gamer in this generation.
http://www.eurogamer.net/articles/2013-11-23-whens-a-free-to-play-game-not-free-to-play
I won't give my opinion here to not created discody between the fans (in fact Sony will follow the MS example if they have success).
I will quote the Forza 5 example for reflexion.
"In Forza Motorsport 5, the problem runs deeper - the economy that's the backbone of the series has been altered, and it's too easy to come to the conclusion the changes have been made to make way for microtransactions. Unlike in older Forza games, cars aren't offered as rewards for success: instead, the only option is to buy them in a grind that can be augmented by pumping in real-world money.
It's a problem exacerbated by Forza Motorsport 5's drip-feed of cars as part of a $50 season pass, a number of which are being reintroduced from earlier games. And even when you've bought them as DLC, in order to own them fully in the game they have to be purchased using in-game currency - or, of course, by pumping in a little extra money of your own. The game's creative director, Dan Greenawalt - a smart and passionate man who I suspect isn't behind these decisions - admitted the season pass hasn't been wholly popular, but that people are enjoying it and redeeming it, and that it's keeping them playing the game for another 6 months. He compared it in some small way to a gym membership - but the problem with Forza 5's membership is that having already bought the gym and paid a subscription, you're then asked to pay individually for each piece of equipment within."