I hope it's on the way, but I don't think the Pioneer Na is yet a sign of this revolution. This detailed review didn't leave me in a hurry to go get one, anyway:
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It seems that $15 per kWh of storage should be achievable with them. At this price, it's trivial to install enough grid-scale storage to completely move off fossil fuels in more southern areas.
That still leaves an Additional overhead due to power electronics and assembly but all in all it's a pretty impressive development.