Joystiq has posted a tour of the installation process for GameTap Lite, as well as an examination of performance for the emulated games.
When it comes to PC perfection, however, the Mac client can't even be bothered. Finding a few DOS and Windows titles hiding in the library, we attempted to boot them up with a huge grain of salt. Said grain proved useful as the client downloaded our games, then immediately rejected them in a crashing blaze of glory. This was, of course, totally expected, but we were really looking forward to some Willy Beamish.
A few minor quirks aside, the first release of GameTap for Mac is solid. The titles that support online play perform just as well as they do on the PC, which means that now everyone can appreciate the multiplayer joy that is Twinkle Star Sprites.