I think it is difficult now to sell the Z9 as there is not a lot of interest in a used Z9 even if it is priced competitively. I base this on trying to sell mine on this site and seeing what happens when others post theirs on this site. There are a lot of them for sale. I ended up selling mine by trading out photography trips with a tour guide leader for some of the cost, it worked out well for both of us. I bought the Z9 when it first came out, used it until the Z8 came out, bought one, then bought another one. So far no over-heating issues but then I don't shoot a lot of video. I did shoot 20,000 images, over a period of days, in Antarctica without any problem. However, the battery life sucks...I don't know if it's just one of my cameras or both, I need to investigate this, but at one point I only got 59 photos on a fully charged battery, it was 20 degrees out. I have nine or so batteries so it's not a problem, just an annoyance for the most part. I can't decide which functions to put on the available buttons I already have so certainly don't need more buttons and I can't really remember what I've set them to anyway! I always remember what the AF-ON is set to, but always have to check the rest. I love the Z8 and the 600PF, a really great combo.