I'll fully admit that the initial launch titles aren't that interesting. It's the potential of the service that truly astounds me. 1,000 games within 3 years? Virtual Console has like half of that in America.
I also think the interface of the service is brilliant. You start out with an empty, virtual game room (think PlayStation's Home). As you buy games your virtual space fills up with models of the actual arcade games, complete with sound effects, attract sequences, etc. If your friend has the same game as you do and he has a higher score than you a spot above the arcade lights up alerting you of the fact, challenging you to best his high score. It adds a social aspect to these classic games that you would otherwise lose interest in after a few minutes/hours. It gives you a reason to come back to Centipede again and again.
There are a few other neat features that sound very promising. First, you can send homemade challenges to your friends based on your accomplishments in a game. For example, if you get to the 20th level in Centipede you can create a customer challenge and send it to your friend. Second, each of the games has a practice mode that will allow you to "undo" a mistake (sort of like the Sands of Time). So if you just want to beat a game and don't care about a high score you can use this mode and if you die you can rewind the game and try again. Brilliant!