
It's available to purchase, (99€) with a 3-5 workdays delivery time, but I noticed that it says 'Available Soon' still on the Steam Hardware page.
I was clicking around to see what it looks likes for purchasing the Controller only to practice for when the Steam Frame comes out.
That's it, nothing essential but worth noting. Even if it says Coming Soon on the Hardware page, it might be ready for purchase on the actual page for the Steam Frame. So if you don't want to miss a milisecond of buying time, upon the drop date, I recommend being sure to be on the Steam Frame page itself.