I am not convinced hybrids make any sense at all. They are a spork or Betamax video in some respects, a stepping stone to full electric with all the expensive heavy battery and motor kit to go wrong but not yet enough autonomous electric power and range to prevent pollution and noise in towns. I know in the example earlier it was stated that Lexus warranty their kit for ages, this is clearly a good thing, but I wouldn't want the bills to fix a Prius or Insight or similar 5 years down the line. I have seen plenty of examples suggesting that many hybrid solutions use more fuel and certainly more resources than an efficient and much lighter diesel or even petrol solution