Any positive experiences with buying it via download? I'd like to play it now, because I'm impatient, but I also like having the discs. If there aren't any considerable draw backs, I might just download it tonight, but the only other time I've bought a game via download, it only allowed three activations of the game. That's pretty lame since I know I'll inevitably screw up game files while tweaking things and I'd like as many installs as I need.