Tried getting mine today from Best Buy. No dice.
So last month I bought the Performance MX from Best Buy for nearly the same price ($69.99). I just happened to be going through my YT channels and saw MKBHD posted a review of this 'MX Master', a device I had never heard of. It was then I realized Logitech updated what I had just purchased, and it wasn't much more money. When I found out that this one has Bluetooth 4.0 on board AND a dedicated horizontal scroll wheel, I was in. That's worth $30 more to me, as I never use the Back/Forward buttons on mine anyway, and getting the Logitech receiver out of my Mac Pro would be a nice feeling. I was on Day 29 of my 30 day return policy, so I packaged it up, made sure my local Best Buy had it in stock (website said it did), and was on my way.
Returned the Performance MX. Went to go look on the shelf, and nothing. They even took away all of the Performance MX's they had on the shelf. Went to go find an associate, who said "It looks like we have one in stock, but it's not on the shelf. So...yeah." Wouldn't look in the back for me.
Went home empty handed. Using my Magic Mouse in the meantime, which is an awful little thing.