I honestly don't think it's either. I used to believe that SA2 was the best Sonic game, but I personally am gonna have to put it behind SA1. While they both have great soundtracks, solid level design, and fun gameplay, I feel that the treasure hunting in SA2 wasn't as fun as it was in SA1, nor was the shooting.
The only thing that SA2 has that makes me enjoy it differently is grinding and the Chao Garden.
Sadly I did not play the sonic adventure games during the sega consle period, I played it's remakes Sonic Adventure DX director's cut & Sonic Adventure 2: Battle. @Hazard I definitely agree with the Chao Garden. :)
The only thing that SA2 has that makes me enjoy it differently is grinding and the Chao Garden.