I think there is no debate in the 600$ Price range The ROG ally & Legion Go are the best handheld PC's you could purchase. Both boasting the z1 extreme that are able to play Most AAA Games at respectful framerates. Leaving majority of handheld pc's playing catch up.
In my previous Ally video (should you go buy the ally in 2025) i suggested to buy the legion go. Though only if you are buying brand new.
Not only will this (Round 2) if you will, Show some insight on why i think this. Also Where the Ally holds a massive advantage in. The Used Market.