I had a 8500 back in the day but now have a 9500. Both great radars, and saved me many times. Without putting them side by side I couldnt tell you which one is better. But id say go 8500 just because of the price diffrence. People will fight over V1 vs Escort all day long. In the end they are both great radars and you cant lose with either one.
I still have my OG 8500 you bought for me on ebay many many years ago..
still works FLAWLESSLY.. saved me from jail time as well.