I've ordered many things (mostly Masterpiece Transformers) from AE for a few years now. They are legit and are most times a bit cheaper (by a just a few dollars) than hlj, amiami, nippon-yasan. The catch with AE is that they have poor to non existent customer service. If on the very rare occasion that you have a problem they can be a PITA to get in touch with. It's only happened to me once in the past few years. They only shipped 1 of 2 MP Bumblebee figures and I had a pain of a time (about 2 months over the holidays) until it finally got resolved.
So very good and legit business. However, if something does go wrong it kinda stinks. Probably why they are generally the cheapest option. I still like to use them because you can pay for the item up front, build up a shipment over time of many items, and then pay for my choice of shipping at a later time when I decide to ship. I've ordered from all the places I've mentioned and the 2 that I stick with are AE (for the prepay option) and hlj (if I don't have the cash on hand when a preorder goes up). Hope that helps.