From what I read recently, 10 gridseed units, each of which contains 5 gridseed chips, are capable of scrypt hashing at 3 - 3.4MH/s at a total power consumption of 100 watts, or 10 watts per gridseed unit, presumably plus whatever it costs to run the device to which they are connected (computer, special purpose controller, whatever).
That comes to just about 35ish watts per 1MH/s, which is a lot less than the 150 watt figure you suggest. And the gridseeds are available and running now.
That is awesome if that is the case, but, I still am a bit skeptical. Pre-orders are good way to get to play with people's money. There is every reason for a company to be less than truthful, or embellish their offering in order to secure that pie.
I also have a feeling these things will be DOA when they are given to the customer, I don't mean they won't function, but I think the manufacturer will weigh the profit/loss ratio of when to give you your miner. We will see them on the network long before a singe pre-order is filled.
People already own gridseed units and are currently mining with them at these power consumption levels.