I downloaded Madden 13 and Mass Effect 3. There were no differences to the disc version at all. The only disadvantage is you can't just lend out the game or resell it. But I hardly ever do that anyway.
The advantages are you don't have to change the disc which I think is pretty convenient. And technically you can give the game to up to 2 other people for free by logging onto their PS3 and downloading the game. I was also hoping loading times would be decreased but I don't think there was a difference in those regards.
In the past the PS Store usually updates earlier than 6pm PST. Usually its around 1pm PST. I think EA is just playing it safe so they don't get backlash in case the game is available later than they posted. I'm in the same boat as you Delta, hoping to get a chance to play NCAA tonight European time and not wait till tomorrow for it.