spotted a ROG ally at a Best Buy and played with it a little. I do admit that it feels really nice in the hand.
Honestly I'd be more then willing to replace my desktop pc with a system with this formfactor. I'd get a couple docks so i could plug it into my monitor setup or my tv, as I like to do most of my gaming on the couch. I don't
think battery life will be as much of a concerned as any pc gaming I'd be playing plugged in anyways.
One thing about the Asus ally, it's top port is listed in it's specifications as a "ROG XG Mobile Interface and USB Type-C combo port", which is used on it's laptops to run
an external gpu. It's possible to get a dock that makes it even more powerful when plugged in
I'm keeping an eye on the Legion Go. the bigger screen will be nice. It's expected to have an AMD Ryzen 7040 series APU, which the Ally's Z1 is based on.