i think that's all going to depend on what sort of infrastructure they have (or how quickly they can expand). they will need a shitload of bandwidth and processing power to keep things running smoothly. but in my experience onlive is identical to any other multiplayer game. i played some singleplayer games too and it was pretty smooth. just like a local installation, really.
you should check it out sometime. they give you like 2 weeks free, and you don't need to give them a credit card and then "cancel" before your billing cycle like with most jackasses.
i think it's basically just specialized remote desktop software. the client records your key presses while the server side handles the actual game, and it's sent back to you as streaming video. this remote desktop app i have for my ipad works pretty much the same way, and i play games through it too.
it really does level the playing field, because you can have top of the line PC graphics without coughing up big for hardware like you and me. also, no more installations or long startup loading times. you can enter and leave games as quickly and easily as pausing or starting a youtube video. pretty neat stuff.
as for the 3d stuff, i agree. my nephew brought over his nintendo 3d game thing on thanksgiving, and that shit is just a portable headache. i don't like that anime stuff either.
it's an amazing operating system. my last experience with a mac was in junior high school (the old black-and-white macs), so this is just blowing me away. i can't believe how drastically things have turned around for apple. i never thought the day would come when i would look forward to having the money to buy a top of the line macintosh, but you just can't beat their product line.
and i think you're 100% right about "any sort of desktop." iirc, even steve jobs said that few people will own a desktop in five years.
your processor will decide how you install it. i have a 6-core "gamer" amd phenom, so a lot of stuff was needlessly complicated. if you have an intel, it'll probably be a lot simpler. you need to install an amd-specific kernel (everything you'll need is included in that iso for intel + amd) and all kinds of crap, and then manually enter the cpu's bus ratio during the mac osx setup to even get it to recognize the computer it was installing to, etc. etc. etc.
now that it's installed, i have all my settings stored in apple's boot manager, which is sort of like a windows batch file (i added entries for stuff like busratio=16 etc) and now it all works. one-click startup, just like a real mac!
by the way, the version of osx in your vid is an old one. ios sdk only supports snow leopard (10.6) and up. that's one of the reasons i was having such trouble. you have to use one of the two latest versions (snow leopard or lion) or you can't develop ios apps.