I used Shane Craig’s video walkthrough to install the DSU image. It’s almost like running a virtual machine, so there’s no partitioning or big warnings about bricking your phone if you do it wrong.
(708) How to install the Pixel Experience Android 13 ROM on your Surface Duo (Important pinned comment) - YouTube
Since this went on a Duo generously shared for the purpose of installing stuff, I’m tempted to flash it and have it run only android 13 (and also maybe Windows 10x) but the instructions to do so are slim and involve a few things I’m not familiar with.
My impression after playing with it for 30 minutes - it’s android. Face unlock works, so that’s cool. And it comes with some neat wallpapers. But other than that, it’s just Android with all the same Android apps, same gestures, similar multitasking to what the Fold got with the dock bar. OneNote works, pen writes nicely. It treats the Duo as a single screen tablet, so everything opens spanned, but many apps split nicely down the middle in landscape on a tablet anyway. Gmail looks nice. I’ll play with it more, but for now, nothing jumps out as being super awesomer than microsoft’s Android with handles to move things between screens.