Very enjoyable - My eight year old son (who was up until 2 weeks ago addicted to network quake) is now addicted to network Armagetron. Runs perfectly on his cube (with an upgrade card) and my MB Pro.
Graphics on the wall are a bit lame and there is no big "You are the winner/loser" screen at the end of rounds but the gameplay is amazingly slick and fun.
(3 minutes in photoshop fixed the lame graphics on the wall).
Well done.