On the positive side: EG3 is a very enjoyable arcade racing game to play. To do well in this game takes strategic thinking (to get the most out of available money, weapons and boost) and is visually very rewarding (this is a rewarding game to watch being played). The learning curve is pretty steep, and reminds me a lot of a modern Wipeot 2097. The AI opentents have a similar feel to Ridge Racer (ie some are easy to catch, but to come 1st is real challenging). My two boys (8 and 9) like working together as a team, which makes a change from beating each other up in games like DoA2.
On the negative side: The controls are difficult to use at first (and I almost feel like I need a third hand to switch between turbo boost and weapon usage). After playing games like GT3 I expect more tracks and a wider variance on how the various vehicles feel.
Conclusion: You should be able to pick this game up pretty cheap now (I did anyway) and really get your rocks off on this game. GT3 has far more wow factor, but EG3 is more of a thrill to race.