do not preorder
there are several reasons for that. the first one is obvious: you might not get your miner in time or if you are really unlucky, you might not get it at all.
the second reason is that money of your preorder is used for the development of big data centers that will compete with you. we have already seen this happening with Bitfury, KnC, BFL, aaaand Spondooliies tech...did I forget someone?
how about you? what is the first rule for ya?