Some of the booths were set up in a way to keep you there for as long as possible - I guess the more people huddled around the booth - the more attention they get?
For example, they make you line up and once you are in the stand they give you a long explanation of the game controls before you get to play - taking a good 20 - 30 min of your precious time.
But I don't like having subscribe to each game I play - rather pay a flat fee. Some games charge you 350 yen per month. You cant just download it and then end the subscription because every time you start the game, it checks to see if your subscription is valid over the network.