In my opinion, it's poker, because it's a game I know and the site doesn't ask so much about your stake and winnings, that's reason enough for the site not to steal from you.
Generally speaking, poker is a strategy-based game therefore, cheating over it might be difficult. You are against at your fellow players on a single table playing in a single set of the deck.
But when we put that game
"online", that's where the flaws might occur as we don't know if we are really playing against a human or we are just dealing against a bot.
Some of the online casinos today do have their own verifiers to show that everything is fair. As we know, even with the bet verified properly, not all can understand how it works or still they aren't sure if it's true. It's just a matter now of how reputable that site is for them to somehow trust that everything is fair.