Well, obviously, it greatly depends on your own network speed when downloading the games. Some of the games can be a few gigs in size, and if you're downloading at 50 kb/s, that's going to take awhile

but if you have a nice cable connection, it shouldn't take more than an hour or so.
I haven't tried it out yet, but it seems like a good idea. There are a lot of games that I don't want to bother trying to find, and this is a great solution. One drawback: nothing to sell. You can't sell the game to someone else when you're done with it..