I like the ZONE for the way they display games in a window, shows ping, players, game description, etc. I like GameSpy Arcade for chat (admins allmost everywhere), search options and a few other things. And of course... dedicated servers
What I dont like about the Zone is the lack of admin, how flooding isn't well blocked. Morons (Though I find Battle.Net to be much worst). I don't like GameSpy for the lack of details in some sections and that recently added Advertisement that shows up when you just launch the program.
If ever TheZone figured a way to implement Dedicated servers to its current internet gaming platform I would ditch GameSpy Arcade right away!