This was probably one of the better videos done. The thing that the buyer must be aware of is this is not a console, it is a PC. This brings a tremendous amount of flexibility, and with that comes caveats that things wont always just work like they do a console. If you are already a PC gamer, you are likely someone is is accustomed to working through these issues, but if you are someone who is not PC tech savy and really just wanted a Switch Pro, this device may leave your frustrated. Game development on consoles is more than just creating good code, its about creating a smooth problem free experience that just works.
The OS is basically in the Beta stage right now, it has issues but luckily its software related and as long as Valve stick with it, they can iron them out over time. Lucky or unluckily for most buyers, it will be weeks or months before you get your Deck and many of the current issues will likely be resolved.
2) They had over a 100 thousand preorders for just the combined 256/512 models in just the first 90 minutes arstechnica has an article . Remember those numbers are just the first 90 minutes and doesn't include the cheapest sku.
So we really don't know how many preorders Valve has for the Deck other than we know its over 100k. Did you ask yourself why they didn't report the numbers for the $399 SKU? I have a hunch that its not because the numbers are huge and would be very flattering to report, but instead they don't want consumers to know they allocating minimal inventory to the SKU. It is likely the model they are losing the most money on, but by having it they are able to market the Deck with a "starting" price of just $399. That model was created because they wanted to be able to market it as such, but there intent has always been to get buyers to upgrade to the more expensive models where they arent losing a fortune.