The current hybrid technology produces the most fuel-efficiency gains in stop and start driving. In other words, it works much better for taxi fleets than for family road trips.
Well, most of our driving is stop and go, in-town driving. However, it doesn't make much sense to buy a family car if it doesn't work for road trips as well. Especially since it is cost prohibitive to fly for a family of 6 when we can drive for 8-12 hours for a fraction of the cost.
Actually, it can make sense to buy a family car that doesn't work for road trips. Save money (fuel + price) by buying a smaller car, and rent a van for the few times a year that you need it.
I have not found that to be true for us (again, a family of 6).
Renting a van will cost $500-$1000 for a week. If you do that 3-4 times a year then you are talking about approx $200/mo in monthly payments that you would have to save.
