Easily the first one.
At least The Amazing Spider-Man had something original about it - emphasis on real stunts, and an attempt to be more realistic than the Raimi movies.
Amazing 2 just screams, "Wait, come back, we'll do all the Raimi stuff if that's what you want!" So Amazing 2 has a Raimi-style suit, the over-the-top villains, the campy comic relief characters, the 60's Spidey theme...just compare the colour scheme of the two films. Amazing 1 is realistic and shot on digital. Amazing 2 is bright, colourful and shot on film.
I sense the hand of Avi Arad....