I have X1 Nano Gen3 but I'm not even thinking about upgrading to X1 Garbon Gen 13. From my point of view X1 Carbon is not a successor. It's worse. With the right Ctrl button replaced by a useless fingerprint reader, Lenovo can shove it.
I purchased a 32Gb X1 Nano (Gen 2) with every possible option and upgrade. It's been a solid performer but battery life has been marginal and heat management has been terrible. I had to buy active cooling pads for both home and office. It's been decent as a lightweight workstation and can drive two 4k monitors. But when it gets hot enough to be uncomfortable on one's lap, it fails in an essential function.
First thoughts as a Gen 1 Nano owner are "it's not 'nano' - not a replacement". Footprint was the key item for me. But after reading the review in early January I am convinced - unless Lenovo announces a true nano replacement at CES, this looks like it will be my next laptop.
For the nano Gen 2/3 owners that also commented, I feel bad that Lenovo decided to put "P" processors in the nano Gen 2/3. The cooling solution is designed for the 10-15W Gen 1 CPUs, not the Gen 2/3 P series that can hit 60W. Why Lenovo did this is nonsense to me. My gen 1 runs all day, is near silent, and is just overall awesome. The latest Windows 11 updates are starting to stress it, however - it seems time for an upgrade and the new X1 Carbon looks like it could be the one - it's got the exact set of features I am looking for in a replacement (other than I wish it was a 13", but the footprint isn't that much bigger so I can deal with it).