Glad to hear that others have had success with the Priceline reservations. I, however, have not been so lucky. For the posterity of this thread and different experiences, I'll pass along what I've encountered so far.
I booked an express deal last Thursday for a late summer stay at AKL-Jambo. Like others, the confirmation number from Priceline did not work in
MDE right away and so I waited (as well as confirmed through Priceline support chat late Friday that it could take up to 48 hours). The number still was not working yesterday (Day 4) in MDE. I saw on here, however, that others who booked the same resort in the last few days had been able to link their reservations using Priceline's confirmation number. I contacted Priceline support by chat again last night to ask if they could confirm the reservation and provide the internal Disney confirmation number (which should be available as soon as Priceline made the booking even if Disney's internal number was not yet connected with the Priceline confirmation number - basically, give me Disney's internal number so I can link the reservation in MDE). The support person said that she contacted Disney Wholesale, who told her they would need Priceline to fax a request to them and that it would take 24-48 hours to resolve. She was not able to give me a Disney confirmation number. Something didn't sound ... right.
Today - day 5 since my booking - the Priceline confirmation number still wasn't recognized by MDE. I contacted Disney Wholesale myself to see if I could get a confirmation number. The Wholesale person was immensely helpful and knowledgeable - even though, after taking my name and reservation dates, she had to tell me that they had no record at all of any booking under my name. She even checked AKL and AKL-Kidani to see if they'd moved the reservation there. Nothing. I asked how long it usually took for Priceline bookings to show up in their system - up to 48 hours. She thought that 5 days was unusual and that it seems as though Priceline had not made the reservation. (I'll add that, as of last night, AKL-Jambo was still showing up as an express deal for the exact same dates that I selected).
I then spent an hour on the phone talking to Priceline support and then a manager (the latter couldn't talk fast enough trying to get me off the phone after it was escalated). The support person told me that a case already had been opened (for what??) and sent to the back office - which he said would take 10 business days for the back office to resolve. After objecting to that, he put me on hold to speak with Disney Wholesale - when he came back, he told me that he was told Disney's practice was not to release that information until 10 days before the stay begins (completely false). I kept trying to explain that was not the case - and that if Priceline in fact had made a reservation it should be in Disney's system by now and an internal Disney confirmation number available. He said that they were contacting Disney, but again it would take 24-48 hours for anything to show up. I was finally transferred to a manager - who also put me on hold to contact Disney only to get back on the line and tell me that I should hear something within 3 days. I kept reminding them that they had charged me for the booking immediately, but so far could not provide any evidence that they had actually made the reservation with Disney. So it seems as though I will be waiting at least several more days trying to bring this to resolution. I'll continue trying MDE to see if the Priceline confirmation works, but I'm not optimistic. Not that I was expecting it, but none of the Priceline support ever even suggested a refund or cancellation option.
It's a shame - as the Priceline express deals seem like something I would use quite often. Clearly they seem to work for most people on here - seems fantastic if it works as intended. It's one and done for me, however, after this experience. Half the price, but ten times the headache.