Well, I regularly use Steam, and I don't use Origin. I've also heard many bad things about Origin, and while Steam is not perfect, it's definitely very good. I would love it if the Wii U used Steam, however I'm pretty sure Nintendo won't except either offer.
Steam, because it has Counter Strike and knowing Nintendo, they could make CS kid friendly
Realistically speaking, I absolutely do NOT want Online Passes. I already bought the damn game, I should be entitled to whatever content it has without having to pay extra, right? Or...wrong, depending on how you look at it. Still, I pick Steam because of all the expereinces I've had over it. Origin I hear is bad, and I also hear its the only way to get an online version of BF3 for PC users, sad choice for DICE but I'm not the company so I don't make the decisions.
That way, we could play Sonic Generations on our Wii U's full HD and 3D (If Wii U has 3D Support, which I think it will) with COMFORTABLE controls. Also, there are free games like Portal 1(Well, I think it was), Team Fortress and so many good games.