It's the peak of the PS2 era Ace Combats, and maybe the best in the series overall. Good replayability, good plot, great music, amazing battles.

The Ace Meter isn't revolutionary in terms of gaming, but it does a fair bit to help the immersion- of course the enemy would want to send their best against someone who's mercilessly cutting through their forces.

In general, it's great all around, and definitely worth it.