Graphics weren't amazing to be honest, but I wasn't expecting XBOX quality...
I think internet speed is more important than processing power honestly.
I do think that it will get boring after a few more sessions until they add more routes, but again this is still in beta and just to work out the kinks.
Also - for all you STRAVA users, you can upload the ride as if you were actually riding out on the island. It somehow thinks the island of Zwift exists and shows it in the middle of the pacific ocean. People have already created a variety of segments of course.