The 809 because it is several years newer than the 876. The last number denotes a refresh so the higher the last digit the newer the model. The 876 was a slightly better model of the 806 three years back and the 809 superseded the 806, 807 and the 808. The added features make the 809 the better option because the amplification capabilities of Onkyo's intermediate (models with a 7 between the first and last digit) models rarely differ to the model below them. The first digit has to change before there's any major difference in terms of audio performance. The higher the first digit, the higher the model and the higher the last digit then the newer it is. The 7 simply denotes a slight stepping stone in terms of features.