The 512 arrived today after all.
They say that comparison is the enemy of joy. If I didn't have hands-on experience with two different Decks I never would have known any better and probably would have been perfectly happy with either one. But I've noticed a strong difference in how the trackpads function between the two devices. Especially when using them for dual-touch typing. On one of them, sliding my thumbs around causes the device to vibrate a lot. I can feel it under my thumbs at the trackpads themselves, and it's quite audible. Almost to the point where I'd describe it as rattling when I really get moving, or especially if both trackpads are going at once. And it's very easy to "press" the button. Just apply a small amount of pressure and it gives a satisfying "click" to let you know it has been pressed. Sometimes I click it and I think "that was a little too easy to click!" and it concerns me that it might click unintentionally at times. On the other Deck, the vibration is much more subtle while sliding my thumbs around. I can feel a light vibration in the palms of my hands at the back of the device, but not really under my thumbs at the trackpads. It's not audible to the same degree as the other one. If I put my ear a couple inches away from it then it sounds about as loud as the other one at normal/comfortable usage distance (about 2 feet). And pressing the trackpads in to "click" them requires significantly more pressure before they finally click. It's actually pretty uncomfortable having to press in so deliberately and so firmly, that I think I prefer typing the slow way with the d-pad and A button to select each letter. And when it clicks, the click is much more subtle and toned down compared to the other one.
Now I'm not fully satisfied with the trackpads of either one. It seems like one is far too sensitive and the haptics are too strong, and the other is far too insensitive and the haptics are too weak. It seems like the ideal is somewhere in the middle. Yet both devices have the same (default) settings as far as the trackpad sensitivity and haptics go.
For some less important comparisons, namely the carrying cases, I'm finding similar results. The 64 GB model (and I believe 256 GB model) carrying case is all black, with a grey logo outside, but also has a white strap inside to help pull the Deck out of the case without having to tip the case upside down or pry the Deck up by the joysticks.
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PCThe 512 GB model carrying case is black on the outside but the zipper pulls are white, has a colored logo, has a grey interior, and a black strap inside for pulling the Deck out. And the zipper itself is a whitish grey color.
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PCI always thought the white strap inside the 64 GB case was a little weird and out of place (and not just because it's sewn in a little crooked), but other than that I've found it to be a perfectly fine functioning and looking thing. The "special" 512 case, on the other hand, is just ugly to me. I think the white zipper pulls are absolutely hideous. The grey zipper is weird and out of place. The grey interior fabric looks okay but I prefer the black fabric. Also I think that the grey fabric causes the black strap to look a little out of place, even though the black strap does look a little nicer on its own to me than the white one in the other case. And the colored logo on the outside is made of a different material. It feels like it's made of a kind of rubber or silicone, with a slightly sticky/grippy feeling. And it's much thicker, extruding from the surface of the case a few millimeters. Seems like it would easily catch on something and get torn off. Whereas the grey logo on the other one is completely flat, appearing to be a vinyl sticker or something similar.
All in all, I think I prefer the non-special carrying case over the special one. If it had a black strap instead of the pure white one inside it, it'd be perfect. I think I'll swap the carrying cases and keep the dark one for myself.
Additionally, the 512 GB Deck (and carrying case/accessories) smells awful. It smells like burnt/melted plastic and fried electronics. The 64 GB Deck didn't have a particularly strong/noticeable odor. I have recently developed (or noticed) a personal quirk where I "smell" things to see how hot they are, like when I pull food out of the microwave I give it a sniff to see if it is warm enough. It's probably not really about how it smells and more about my face being more sensitive to temperature than my fingertips, so it can more easily sense the heat rising from it, but since my nose is right there and it's something I usually do with food, I've gotten into the habit of giving it a sniff while I'm at it. Anyway, all that to say that I was trying to gauge how hot the air was coming out of the 64 GB Deck's exhaust vent and I gave it a little sniff while I was at it. And to me it doesn't smell unpleasant. It definitely smells like new materials. Maybe like new shoes, which have a distinct, but not unpleasant odor, in my opinion. But then again, it's possible that the 64 GB Deck was just as odiferous as the 512 GB Deck, but I might note have taken note of how smelly it was because I didn't think it was unpleasant. All I know is that right now I can't do anything with the 512 GB Deck (or its case) without noticing how awful it smells.
As for the two practical/intentional differences between the devices:
Storage: The internal storage partition for the 64 GB Deck is reported as being 46.5 GB. The internal storage partition for the 512GB Deck is reported as being 465.3 GB. It's a bit surprising to see that the 512 GB Deck has 10x the usable internal storage as the 64 GB Deck. I hadn't thought of it in those terms before. As for storage speeds, I installed a few games to the 512 GB Deck and didn't notice any slowdowns or related problems like I had when installing to the microSD card of the 64 GB Deck. I have inserted a microSD card into the 512 GB Deck as of yet because the largest microSD card I have is the 256 GB card and it's currently in the 64 GB Deck, and the 512 GB Deck still has more available storage than the combined total in the 64 GB Deck. But for the sake of completeness, I ought to swap the microSD card into the 512 GB Deck and see if I experience the same kind of slowdowns as I did when it was in the 64 GB Deck.
Screen: The 512 GB Deck has a special laser-etched anti-glare screen. They both show reflections. It's just that the regular glass shows a more perfect/clear reflection while the anti-glare glass has a less detailed or more blurred reflection. What I can say is that I find myself being self-conscious about capturing my own reflection in the regular screen, whereas with the anti-glare screen it blurs the details enough that I don't mind (so much) if my silhouette is reflected in the image.
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PCAnd for reference, I usually have the screen brightness turned down pretty low on both Decks. In the images above, I put it as low as it will go, and then up 3 notches. Here's how it looks with the brightness of both displays turned up to the max:
Valve Announces Steam Deck: A Handheld PC 
Valve Announces Steam Deck: A Handheld PC
