Important edit: The Steam Controller is not totally out of stock. They are toggling availability to limit orders. If you have not yet gotten one, continue checking the site.
Who all managed to get one?
Who’s with me in the “impatiently has to wait for them to return to stock” camp?
What excites you most about the Steam Controller?
The apparent issue is the payment processor (visa/etc) getting overloaded. To avoid it in the future it sounds like you can preload your steam account with the funds (~$108usd where I live due to 8% tax), which will let you bypass the worst of the checkout errors.
FWIW, I was getting the same checkout error as everyone else for half an hour while trying to buy with steam wallet credit.
Yep, Steam Wallet here too. I definitely hit Continue at least 100 times before it processed.
RIP, there really should be a less shitty way to buy stuff like this