I've got an Asus Rog Ally and I think it might be my favourite object. Out of all the objects I own, and even including those that I don't own, it is objectively the best object.
It's a Steam deck, but more powerful, and Windows-based so you can install Game Pass, the Epic Games Store, GOG, the terrible Ubisoft one, or whatever you want as well as Steam without any more fiddling than you would on any other Windows PC. Games run well and look amazing on the machine, too. Albeit only for about an hour before you have to recharge the battery.
As that alludes to, it's not all positives compared to the Deck. It lacks the touch pads, so you can't realistically play RTS games or anything that is mouse-controlled. You can use a thumbstick as a mouse, but that's just terrible. The Windows thing is a mixed blessing really. It gives you flexibility, but it gives you a UI that is not designed for a handheld device, and it also inflicts all the fun of Windows. One day, my Ally suddenly became locked in a weird resolution so all the icons were absolutely tiny. It turned out that Windows had installed an update that over-wrote the device's graphics driver. Fixing that was an absolute nightmare. It took hours, and I had to go out and buy a wireless mouse and keyboard to attach to the device in order to click on the icons and boxes I needed to, as prodding them in touchscreen mode was literally impossible. It also cooks it's own SD card reader after a while. This isn't a fault that affects some machines. It's inevitable.
On the positive side though, and most of this applies to the Deck as well, a handheld PC like this is a genuine game-changer. I've always loved handheld gaming, and in many ways this is exactly what I've been dreaming of for decades. My entire PC library is right there, accessible wherever I go (for about an hour) so I can play Red Dead Redemption 2 or Starfield in a car park. For about an hour. Starfield looks and runs better on the Ally than my desktop PC. It doesn't make it any better as a game, unfortunately. The fact that it is a PC gives it a huge advantage over the Switch in terms of affordability. Obviously the unit is expensive, but then you can get the games for a lot cheaper. Switch games don't really come down in price much. Breath of the Wild is still £40 second hand, for example. If you use Steam Sales and CD Keys, you can get fantastic fairly recent games for under a tenner. That's not even taking into account Game Pass.
What's more, if you happen to be a dangerous renegade, a rebel with no regard for the law, the libraries of previous generations are there through the magic of emulation. I play PS2 and Xbox 360 games on the Ally as much as I play PC games. I can finally play Geometry Wars 2 again! In a car park! For about an hour. There is a program you can get for the Deck called Emudeck which organises all your emulation stuff in one place and makes it simplicity itself to use them. It is available for Windows as well, but you have to sub to their patreon for a month as it is currently in early access. It's well worth it, frankly.
A Steam Deck for £350 is such a no-brainer in my opinion. It's so worth it. A second hand one for something like £200 is tempting even though I already have a Rog Ally, frankly. It's even not too difficult to upgrade the SSD to a much bigger one. I have a 2TB SSD in my machine now, so I have hundreds of ROMs and about 20 full size PC games installed on there and still quite a lot of free space. I also have an unused 500gb 2230 SSD that could find a new home in a second-hand Steam Deck…