I also haven't played Triple Town, but I want to note there are multiple ways to go about free to play. I love the model Valve does with TF2. A player will be able to unlock a large amount of weapons through achievements and drops without spending any money. People may argue about balance, but there are no weapons which 100% outshine each other. Being a paying user doesn't really affect how well you'll do in game. Dota2 takes this further and you only pay for cosmetic items, with your character's ability having absolutely no correlation with how much you've spent on the game.
LoL takes a different approach: You can spend money to unlock characters. However you steadily earn money from matches. I'd call this a middle ground.
Most social and free to play games on phones and facebook take in my opinion the worst path: Paying directly and dramatically influences your ability in the game. I dislike this approach for a variety of reasons. The biggest is the ways it influences other design choices. I'd love to have a little game revolving around growing a good farm or city on my phone, but all the games I know about take the social approach. This means I have to go and wait around for something to build unless I pay, instead of having fun playing a little game. Imagine if tamagachi used the pay to win approach? That rich kid in the playground would've had an awesome pet, and everyone else would be left with a starving pet.
I agree, I have tried a few games with the wait or pay to advance dynamic. I much prefer to be able to progress as much as I want when playing, limited by the time I have to play rather than when the game wants to halt my progress.
The other issue is that it seems like often paying wouldn't be much fun either as it makes the game to easy.