Got one of the first ones, 4gb, had to wait. I got one of those kits with the joke-size heatsinks, and wound up putting a Noctua fan on the box, and now it stays in the low 40's. Now, I'm a fan of pies, and use a few around the homestead. Most have a webserver (NGINX), MySQL or MariaDB, the camera, some perl CGIs to show me logged data...and are loafing as is (I think one is even still a pi 2). Like they work really hard for half a second once a minute unless I'm streaming the camera...
Now this thing comes along, and it's roughly as quick as say, my old Lenovo Core2 duo laptop. Which isn't super, but is way not-shabby (added SSD).
It's usable as a desktop. Arduino IDE is on the slow side, and won't support ESP32's here, but it's slow on my 7th gen i5 too...
So, I'm struggling with a use-case for it, other than a bench toy. It's not going to make linux controller stuff hard realtime - that's linux' fault, it's a pre-emptive opsys, so I use slaved arduinos for things like that (for example, ECM for a backup generator). I don't need another low grade desktop.
I'll be interested to see what people use these for that you couldn't do with one of the earlier ones (using less power). I tried really hard to make this run out of 4gb and it took chromium with many tabs open, all the above background stuff, and finally, Arduino pushed it into swap. Linux is efficient!
I wonder if Eben is going to be right in the end - he predicted 2gb was going to be "the one".