A little update on my AE order experience to date... I'm currently running at a 50% delivery success rate. I've received 2 of the 4 orders I've placed.
For one of the MIA's, the seller provided an invalid tracking number from the start, so we had no idea if/when/where it was ever shipped. When it didn't show up by the protection deadline, I filed the dispute per AE procedure and was refunded the full amount within a day. Happy with the resolution and willing to roll the dice, I turned around and reordered the same item. Hopefully I'll get a real tracking number this time.
For the second MIA, tracking showed the package arriving in the US, being transferred to my state, then my town, then it disappeared entirely off the radar... I'm guessing this one is the fault of the USPS and not the AE seller, so I contacted the seller and requested an extension of the protection deadline so the seller wouldn't get stuck holding the bag for USPS's shortcomings. Hopefully they can get the package tracked down eventually... but it's probably wishful thinking. If it never shows, I'll file for a refund under the protection policy and reorder from the same seller.