I would join a forum or two comprised of owners of the hybrid you're thinking about buying and ask such questions there. I'm sure owners can help guide you.
If you consider yourself an environmentalist, then you're better off with a diesel, if available in your country. During emission testing, all hybrids performed worse than expected, with higher levels of VOCs (cancer causing toxins) than manufacturers want you to know.
Only one hybrid performed better than all the diesels, and that was the Prius plug in. Choose wisely...
They test clean air, energy efficiency, and green house gas emissions. Those three ares are given equal weight for the start rating. Since fuel efficiency directly correlates to green house gas emissions for cars without a plug, an efficient car is going to score well in stars, even if the other emissions are high.