Their website has worked fine for me for past sales, I never have seen the crashes like you see on some sites, so you should be good. I'm always there the second that the item becomes available, and the process has always gone smoothly. They say that they will only have about 800 decks available to sell, so based on previous sales, I would guess that they will sell out in 3-5 hours, but don't hold me to that. If you're not there in the first minute, don't worry, you will still be fine.
Quadfather, this site usually sells to the US and the rest of the world, giving us some easier access to a few of the decks already released in the China region. There are more than 800 decks printed, it's just that they only have 800 available for sale in their store to "the rest of the world". Many people see their numbers and assume that there are only that number of decks total. I'm not completely sure, but it may be a deal where what doesn't get sold in the China/Asia region is made available for the rest of the world through Aloys. this is in addition to Aloys' normal custom decks. I have purchased many decks through Aloys Studio over the last 5-6 releases, and they seem to be good folks. They ship quickly and are easy and friendly to deal with.