I've been wanting to talk about this since I saw IGN's article.
Personally, I don't mind free to play games, as long as it is done right. This means:
I can progress through the game without feeling the need/pressure to spend money. Example is Real Racing 3 on iOS. The past 2 installments were paid, and they were great games. The third is free, but I was still able to finish the game without spending a dime. Only thing I could have got is stuff to save me time from playing the game (time-savers), which defeats the purpose of playing the game anyway lol
Furthermore and kind of going along with the last point, this one has some leeway; there should not be any modes/level/map/gameplay in the base game that require cash to unlock. DLC is okay. But when I download new game only to find out that half the levels require me to pay up with no other alternative to getting them, it can make me disappointed. Not always. If I like the game enough, sure I will pay a dollar or two to get more levels or whatever. No problem. If DLC is added, that isn't as big of a deal. But if a new game has content I can only play if I buy, it makes me feel cheated, even if I didn't pay for the game. If you're going to give me a free game, give me the whole thing, then you can release DLC later. Don't have DLC when the game releases. It probably looks like I'm making a bigger deal out of this than I want it to be. Anyway, it gets blurry because many iOS game have "Lite" versions which are like demos with in-app purchases to get the full game. This I don't mind, because it's not a free to play game, it's just a demo.
Basically, I can enjoy free to play as long as I can progress through a game normally just as if it were paid, and I'm not pressured to spend money. Those are the most important parts.
I also want to say that it can get on my nerves when, on the App Store, I buy a game, and then they update it with new content that I would need to pay for. The thing is, they used to do this all the time for free, update a game with new missions/levels/etc for FREE. You bet your ass it was awesome. But now, for many games, each new content update is an opportunity to get money instead of making customers happy with free new content. I know, it's DLC, and I don't really mind DLC, but at the same time it can sometimes get me angry. Like, I thought I bought the game, but I guess now you're telling me I only bought half of it.