Voltorb Flip all the way.
When I first heard about the change over I thought it was silly, changing a whole aspect of Pokémon that has been in every main series games because of a few busy-body parents complained their children got addicted to gambling because of a Pokémon game (WTF?).
But then once I got the game I thought it was great, now I can actually win decent amounts of coins without having to fork out for them. Buying 10,000 cions got to be a large amount. At first I thought the item prices were over-priced, but then once you get the knack of the game you can get really large amounts of coins before you know it. I've only been playing Voltorb Flip for a few days now and already have over 8,000 coins, it really doesn't take that long before you're swimming in coins. And I've never beaten past level 6!
What I also like about Voltorb Flip is that there is strategy involved, not just luck and timing according to others. While the Game Corner is no longer a Game Corner as such, now it is a fun mini-game that I can actually play and enjoy.