I’ve been watching some YouTube videos about the new handhelds, and honestly, the Xbox Ally and Xbox Ally X are pretty disappointing. Even with the Windows advantage of having access to all the games, the FPS is still worse than the Steam Deck's Linux. After checking out most handhelds, I think even though some may offer slightly better FPS performance, the Steam Deck seems to consistently have the longest battery life.
While many companies have released numerous handhelds and versions, Valve has only launched two models, LCD and OLED, yet they maintain the upper hand in terms of quality.