Made my first order with OMP at the start of this month, as my usual Asian online store (Ehobbybaseshop) makes me think that they are winding up (in the last year they have had less and less items on pre-order each month, and nothing beyond March)... so I need a new source for JP exclusives that get released in Asia that aren't available on HLJ or Amazon Japan (like the TakaraTomyMall exclusives and Ehobby exclusives).
(for those wondering why I don't use RobotKingdom - their bad service processing a couple of my orders and suddenly ignoring my emails when I got one faulty toy, I refuse to use them ever again, or recommend them)

When someone recommended trying OMP for some upcoming items I was looking for (that weren't on EHBS), I wanted to place a small order of in-stock items first, to test them out before placing pre-orders.
I ordered three items that were supposed to be in-stock - JP LG Blurr reissue, JP Infobar (phone) Optimus, and the Hasbro Platinum Edition 3-pack of Cyclonus, Scourge and Sweep.

Okay, the negatives first.

Firstly, their listing for the Infobar Optimus was incorrect, as the Nishikigoi (red) Optimus version is the later, cheaper, non-electronic version, but OMP lists it as the working bluetooth version.
Takara Tomy & Kddi AU X Transformers Infobar Optimus Prime (Nishikigoi) - Working Bluetooth Receiver
There are five versions of the Infobar phone, and the Nishikigoi version is the only one that does not have the bluetooth feature inside the phone. It also comes with a smaller, cheaper display stand for the phone mode, instead of the robot figure-display that came with MP Loudpedal (black Tracks).
Now, I knew that this red "re-release" of the Infobar Optimus was non-working (and bought it knowing that), but other customers might feel misled/cheated by the mistaken listing on OMP, if the online store owner didn't know that this was the one version that doesn't have a working bluetooth installed in it.

Secondly, the Platinum Edition 3-pack was not in stock, despite the online store saying that it was, and allowing me to cart and pay for it... so if they misplaced it or if they have to manually update their online store with stock numbers, it makes it difficult to trust if any of their items, especially their older items, are still physically available, just because their website says it is instock and is able to take your money for it.

On the positive side.

They contacted me two days after placing the order, to see if I wanted to cancel the whole order or get a refund for the missing item.
They didn't ask if I wanted to order something else and charge/refund the difference, so I asked if I could get MPM4 Optimus (or another item if it was in stock yet), and get charged the difference.
They agreed, and sent a paypal invoice for the extra amount. Since Optimus was smaller and lighter than the 3-pack, I noted that it shouldn't cost any extra in postage, and they credited some of the original postage cost from the extra amount owing.

Three days later, the items were shipped. Five days after placing the order, which isn't too bad, considering a day was probably lost working out what to do about the out-of-stock item.

Unfortunately, they were only using DHL, and you have not way of knowing if it will be handled in Australia by DHL (can't use a PO Box address which might reject it back to the sender), or will be passed onto Australia Post at the border (which can use a PO Box address - which I prefer, so that it doesn't just get left at the door and get stolen, or gets sent back to the Airport Depot for pickup if no one is home).
As it was, one of the other people at my house, received it, but left it somewhere out of the way and didn't tell me it had arrived... so I didn't find it until 3 days later.

After all that, the items arrived in once piece.
I'll probably end up pre-ordering upcoming items from there, but just a little cautiously for a while, to be sure that these are isolated issues, not common ones.