So, I bought Super Mario Galaxy 2 to try it out. Here's what I found:
There's nothing special about it at all. You boot it, and it brings you to the normal Wii Menu screen (Point the Wii Remote at the screen and click to continue.) The only difference is that there's a Manual button. The Manual gives you zero information on how to control it - I exited out once by accident before I figured out that I had to scroll *down* to change pages, not left and right. It's a straight scan of the paper manual - Not even a particularly hi-res one.
Once you choose whether you want the Wii GamePad on or not, it brings you to a quick loading screen where it briefly plays the Wii Menu background chime. All it does is forward you directly through the vWii and into the game ISO. All of the features of the vWii are present here - 480p upscaled with black borders around it, etc. Hitting Home and hitting Wii menu bounces you all the way back to the Wii U menu, however.
It really is just a scan of the manual packaged with an ISO that lets you skip over the vWii menu. My save file that I transferred over from my Wii to the vWii was already there, waiting for me. When I tried to create a new file in one of the spare slots, all my Miis that I had transferred to the vWii menu were there.
So... I'm excited that they've made them a bit more accessible, but at the same time, I'm disappointed at the appalling lack of effort that went into it. I was really hoping for more than the vWii experience via legal ISO. At the same time, though, it's convenient not to have to plug in the disk, deal with the vWii directly, and it's nice not to have the same loading times or have to listen to the drive whir. I've owned MPTrilogy since launch. I have the preorder bonus shirt from it, too. But as I'd already played the first two on the GC and the third on the Wii. I barely touched the Trilogy disc, though. But playing it so conveniently on the Wii U...? I may well do it this time.
I wonder how long it'll take the hackers working on the Wii U to figure out how to package their own games, much like people did with PlayStation ISOs on the PSP.
Now, where did I put my rechargeable batteries...?