Just did some more research...... apparently snk, nintendo, midway and capcom aren't willing to participate.
So it's almost exclusively atari namco and sega games. (and a few pc games, usually by teh same manufacturers) And all of the atari games appear to be 2600 games. The arcade games they show in their promo are nowhere to be found.
If this service had come out about 2 years ago it would have been great, unfortunately, on the verge of the release of the nintendo revolution, nintendo is gobbling up every classic property they can find. This means your donkey kong, your crusin usa, your street fighter and even your mortal kombat are going to be on the revolution and probably not on this service.