ROG Ally, Legion Go, MSI Claw, Ayaneo anything - it doesn't matter.
Windows UI is the problem, it's not a good fit for this kind of device, and none of these other companies have mastered the software interface the way Valve has, despite having the unfair advantage of native OS support without requiring a translation layer to Linux...
The ROG has also proved that screen resolution, refresh rate, and hardware performance are compromises to the only thing that matters for a handheld - runtime. Do you want 4+ hours of battery live on a Steam Deck at good settings, or do you want 60-90 minutes of battery life at slightly higher settings that are hard to really appreciate on these small displays anyway? The Ally will use 35W to get 30% higher performance in games, but it uses 230% of the power draw of a Steam deck which is ridiculously inefficient.
Plenty of reviews and YouTubers have shown that the only way to get meaningful battery life out of an Ally is to cap the framerate to Steam Deck levels, reduce the screen brightness to Steam Deck levels, and throttle the processor performance to Steam Deck Levels.
You could have just bought a Steam Deck for half the price and saved yourself all the hassle, and capped at 15W TDP, the Steam Deck is actually faster because Windows is a bloated resource hog that pisses away some of that TDP on irrelevant background nonsense that has no place being on a handheld games console in the first place.
Battery life is NOT the only thing that matters for a handheld. It depends on user case scenario. I used my Deck as a patio or LAN party device so I was always near an outlet. 100w 10ft USB-C cables are plentiful and you can comfortably lounge on a chair or couch anywhere with plenty of slack. Or for camping, I have a LIPO4 battery powered generator for devices that provides ample power. So for me, I don't care if I only get 1 hour out of it. There's always an outlet nearby. Better frame rates, performance, and VRR are more important to me.
Had the Steam Deck for almost a year. Great little console. Recently bought the ROG Ally Z1 extreme version on sale and I honestly cannot go back to the Deck. The high refresh rate VRR 1080p screen is fantastic and no, you don't have to cap the frame rate and drastically reduce the brightness to get any decent battery life. I did many hours of testing at different custom wattage caps and 15w - 24w (same wattage for all 3 sliders) is perfect for nearly any game to run at decent settings and frame rates (over 60) for over an hour of battery life. I also found that running games at 720p and maxing out FSAA makes them look nearly as good as 1080p but with noticeably better frame rates (or lower wattage if battery life matters). There are many Youtube videos with great guides on how to get them most out of the Ally.
Much older games don't even need 15w to play fine.
Yea, it's Windows based. At first I was "meh" about it. But everything runs on Windows and while it may take extra tweaking, to me, it gives the Ally a "charm" about it. Haven't had any major issues.
The VRR aspect is SUPER important. If a frame rate fluctuates from 50 - 80 you don't even notice it because it's soooo smooth. No more putting all settings on low to hope the frame rate doesn't drop below 60.
I tried using Linux on the Deck for a while and I really don't like it. Always having to dig through the folder structure to find anything is annoying. I'd prefer Windows, which I've been using since being a teenager.
The only thing I REALLY liked about the Deck was Steam OS's advanced controller options and recognition of the 4 back paddles. On Windows, Steam sees the Ally as a Xbox controller so it doesn't recognize the 2 back paddles. You can do impressive advanced controller mappings (like mapping a typed cheat code to a paddle button on older games). So between using Armory Crate and reWASD, I get the same functionality with more hassle.
Hopefully MSI puts in 32GB of RAM or adds a VRR OLED screen that DOES NOT USE nauseating PWM at lower brightness (you missed an opportunity here Valve).