Oh yeah, how many arcade games do you know that use SIDS, HUH ??

I know SID is better on paper, but with software tricks it's possible to poor so much out of the POKEY.....
Oh and it has one more channel, it can link two channels to have 2 channels at 16 bit resolution, and, most important to me, the best bass sound. It also handles a keyboard and potmeters.....no SID can do that

BITD I had my 600 XL hooked up to my stereo system, and just listening to the "intro" song of DK was so awesome with the fat bassline.....
Oh and SID is about 4 years newer, which was like AGES in that point of time in hardware developments.
It was also impossible to get any sounds out of it at all using the lousy and ancient PET basic they ditched into the C64 (just to get it done cheaply, typical Commodore....) whereas the Atari had full support of the POKEY in basic with the SOUND command....
Indeed, there is no discussion what was the better system, the other system was just more popular because of the "my neighbor has it so I want it too" factor......