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.
How much heat does the chip generate at that performance level, how long can it sustain it, how much cooling do you need. A raw MH/s doesn't mean much, it could be a peak, it could be what they got in a short time span. What is the life of that chip when it runs that hard, etc... These are all things AMD and NVIDIA have to deal with, before they shoot their mouths off.
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.