My experience was similar to others here. I waited until I saw all the bands my family wanted were available, then added them to the cart. Everything looked good until I placed the order and suddenly my Sorcerer Mickey band was not available. Two buttons popped up, "Try Again" and "Dismiss". I hit try again and the screen errored and showed a purchase for all EXCEPT the Sorcerer Mickey band. That was had been substituted for Gray without my being given a chance to change it. I was only charged for the upgraded ones, not the gray one. I immediately called to get it corrected, but the cast member said they could not do anything until the bands shipped to me in case it was just an error in displaying the gray band. They wanted to wait until I got them and confirmed it was a gray band. Well, I got them and it was gray. I called back and they were able to escalate it and re-enable a new magic band selection option on My Disney Experience just for me (not the entire family). Now I just have to wait until inventory is available again and I should be able to get the band I want.
It's a good thing I have 6 more weeks until our trip, or this would be completely frustrating.