If you're looking for a gaming service with attitude, action games, and support for lots of players, look to Heat.net. Although it can be a bit slow and clunky, Heat.net offers a few niceties that the other services don't, such as 32-player games of Jedi Knight. Heat.net offers two levels of service. Heat.net runs on Windows 95 and requires a Java-enabled Web browser. Once you select a game to play through Heat.net, you leave the Web and enter a chat room, with a much better interface.
Game play via Heat.net is decent, although it suffers from enough latency to be annoyingly slow.
The service's biggest assets are its wide array of action games and its ability to support numerous players. If SegaSoft adds some variety to the game lineup and does away with the need for a browser, Heat.net could become the king of online gaming.