I played this on my 3DS and hated it. I complained constantly (while still grudgingly playing it because hey, it's Pokémon ._.) and thought it was such a waste of time/space. Honestly, it was SO BAD on 3DS, not just in its crappy F2P mentality but just the fact that it was a bad match for the console. 3DS can't multitask so you had to stop whatever you were doing to open the Shuffle app, play that for maybe 10 minutes and use up all your hearts, then close it to go back to something else... and repeat. It was seriously terrible. I was so glad when the Safari Zone event came out earlier this year and I got Cherrim and Cherubi on my first try because it meant I never had to play again. (And I didn't. I haven't opened that app since the day I caught them.)
...but I did go ahead and download the mobile version when it came out recently. They apparently made some edits (Pokémon are have lower catch percentages and they're stingier with the hearts and coins, so it encourages payment a lot more) but I don't even care. It's just such a good fit on phones compared to 3DS that I'm having a blast with it, comparatively. I play once or twice a day to dwindle down my hearts and even though the catch rate isn't as good, it's not nearly as frustrating because it's just so easy to go back in at any time to keep playing once your hearts refill. This is a game that was absolutely made for a device that can multitask and this is where it shines.
I do think the Facebook integration is stupid though. Apparently it's region locked? So even though I know I must have friends on FB from around the world playing the game, none of them show up in my list. It might be the fact that I downloaded the JP app and everyone else is playing the EN app but... another friend of mine in Sweden also got the JP app and he doesn't show up on my list either so it's not based on your app region. >_> It's annoying but honestly, I don't want to play any more often than I already do, so I guess I'm not too gutted about not being able to send/receive partial hearts, lol.
inb4 they release the Safari Zone event on mobile and I stop playing that one too after I catch Cherrim.