Suggestions for upgrading from a Marantz 6005 CD player.....

I have 2 systems in 2 different rooms. I purchased a Marantz Ki Ruby CD player for system 1 and it's outstanding. On system #2 I have a Marantz 6005 which is pretty good. I'm considering upgrading the 6005 but don't want to spend $4 for the Ki Ruby. I've seen used Marantz SA8005 for $600-$800 range. I'm wondering if they would be a significant improvement over the 6005? I've loved the sound of Marantz for 50 years so I don't want to change manufacturers. Please comment if you have had experience with the 8005. Thanks.