I had an Aya Neo 2 at work the other day so here's my brief take on it from an experience perspective.
All the other hand held PC's that aren't the steamdeck are just that, hand held PC's. When you reset or reinstall windows you have no drivers have to plug in a keyboard and mouse to get a driver package of about 19 different things before it's usable then you need to install Aya Neo Space and have that auto launch at startup so that you somewhat get a hand held console experience.
The deck by contrast is just a single recovery image that is good to go and just works.
So I'd say if you want something that just works well buy a steamdeck while it may have less games than the others it truly is a pick up and play experience, if you want to tinker look into the others however I'd suggest you avoid the Ally due to the melting SD card issue for now.