Much better. The a6500 is old and shares the a6300's technology.
Revolutionary for their time as the a6300 is considered one of the first best and usable AF cameras in the world (along with the 1DX Mark II that came out the same year - 2016), but the newer models have improved greatly and have eye-AF as well.
If you don't need IBIS, the a6400 is pretty much the same camera as the a6600, but cheaper.
I debated for a long time between the 2 cameras and I can highly recommend the 6600 over the 6500. Not only is the AF better on the 6600 you don't have to deal with the terrible batteries that come with the 6500. Plus the HLG PP on the 6600 is amazing if you are handing off footage to a client that doesn't want to CC but still wants a high dynamic range image. Oh yeah and the 6600 doesn't suffer from overheating too.
Anybody know when the next sony flagship APS-C camera is coming? A 24MP 10-bit 4k60p APS-C camera would pair great with my A7SIII. It could live on my tamron 70-180 (which is an awesome lens) for added reach and macro
It was 3 years from the A6500 to the A6600, both released in the Fall. I'm guessing Fall 2022 for the A6700. It will be awesome though, I'm hoping by that time it will be at least ProRes RAW.