One thing I've gotta call bullshit on, is the claim that it can reduce fuel consumption by 75% AND reduce greehouse gas emissions by 90%. I'm not seeing how it can reduce the latter by more than the former.
Anyway.....this technology confronts the same issue any new tech would, as compared to piston-tech. Piston tech - having been around as long as it has, has achieved a level of reliability that no new tech can hope to match - at least at the outset. Consumers have come to expect and demand a certain level of reliability/longevity and it's difficult to convince a mass market to be guinea pigs.