As far as can remember, only pre-ordered 1 time from them, that was the Masterpiece Convoy (Optimus) 3.0. However, ended up cancelling it because found it on Amazon Japan for slightly cheaper and already available to ship. They actually did not ship the item on the supposed available month, that was also another reason for cancelling it.
Actually have ordered from them some time before and from time to time, but that was probably the only pre-order with them. So cannot really offer too much insight on the pre-ordering.
Pre-ordering from Amazon was sort of a hit-and-miss. Pre-ordered RE/100 Vigna Ghina from them before and by the time it was available, they somehow cancelled the order. Had to repurchase, but that was only because at the time, they were the one having lowest price, otherwise, Amazon was not really that great as some said.
As far as packaging goes, they were not that much different than any other. Did purchased few kits from them and one of them did have issue, most likely pre-existing box issue when they received it. If there was an item with grading and you selected “collector’s” grade, they will definitely package it better. But Gunplas, no grading what-so-ever, at least they did not have it last time.