I hope they are not a scam. Chances are 50\50 now

I will visit their office as soon as they actually have it in stock before I buy any

You might even want to consider taking a working device with you at that time. Kinda like the old COD (Cash On Delivery) model for items. Or like a real store where you buy stuff and pay for it at the time you pick it up.
Has there ever been a miner vendor like that?
Rockminer tried a program which would put demonstration miners in lots of shops, but it was closed after a while.