As a principally mobile gamer, I've been around the block more times than I can count on F2P games. They are almost all bullshit. Good, fun, usually clever, but ultimately bullshit when it comes to how they monetize the games. I also work in the technology industry, so I'm conscious and sometimes empathetic to small studio's need to make a profit off their ventures, so I kind of understand. Still, it's sad when the next big "free" game with an near-infinitely scaling pay model comes out week after week.
I absolutely love Path of Exile's business model. I commonly use PoE and Eternal as 2 examples of 'ethically' F2P games. I love mobile gaming, but wish most games would take a page out of these company's books.