In general, I do not like to play the smartphone. I prefer my personal computer. I use the smartphone only when there is a problem with electricity or communication.
Pokerstars is the best for me. I tried PS, 888poker, Everest poker in the past and PS is the best.
Pokio is cool, I also recommend KKPoker and Unibet.
I’m not too fond of poker apps. If I’m already playing I like to play on multiple tables, which isn’t good for mobile apps. GG poker app is not bad, I don't know pokio yet, most of the time I use ipoker app.