Seems like the back buttons are a worthy tradeoff if you're looking for a Windows-based handheld. The Ally is faster and has some nifty tricks but Windows holds it back, compared to the snappy, polished feel of the Deck.
For me it is not, I use my Steam Deck has a way to carry the games that I play with a controller on my PC or Console... mobile. I use an Elite Xbox Controller and rely heavily on the back buttons.
TBH I don't think Windows holds it back when once I am in the game (the part that matters) the experience is the same.
> TBH I don't think Windows holds it back when once I am in the game (the part that matters)
Being able to instantaneously[1] pause and resume games on the Steam deck makes for a pretty great experience. The non-gaming parts also matter a lot in a portable gaming device.