First parcel, no issues. Took a little while to get the incoming ticket, but didn't think anything of it - I figured the delivery had been slow, and I didn't care. Picked it up at DYK without any issues.
Second parcel was Amazon, so I had a delivery date. It took Montana Mailbox 7 working days (12 calendar days) to issue the incoming ticket.
I wanted the parcel earlier, so I sent an email 4 working days after delivery, to see if Montana could expedite it. I never got a reply. I was hoping to get at least a "Sorry, we can't help with that", but nada.
MM is undoubtedly big, but I can't see them having a 7-day incoming queue. So they obviously prioritize commercial traffic over individual parcels, meaning one-off packages will take however long they take.
It then took another 9 days for DYK to just pick it up, plus an additional 2 days to get it to the correct office. So about 15 working days, or 23 days total, until it arrived.
Again, DYK is not likely to have a 9-day queue, especially when they pick up every day. It may be the package got held up in Customs, which can happen to any package.
So, while the Montana Mailbox / DYK Post teamup seems a good service, do NOT use it for anything time-sensitive. Or, if you do, allow at least 10 working days after delivery for Montana Mailbox to issue your incoming ticket, and another 10 working days for DYK to have it ready to pick up.