It seem like these 2 cars get the same mileage but the Prius 3 has the Lithium Ion battery. It seems like the 3 should get a little better mileage, Right? Comments?
these are not individual tests done by the epa, it's way more complicated. the 3 may get a mile or two better, all else being equal.
I don't think the battery is the issue - NiMH is standard in most of the world except JAPAN and a couple of models in USA. NiMH is tried and tested - Li-ION is less so.
The Li-Ion battery is used for weight reduction so it has similar capacity to the NiMH battery (and reduced weight/size compared to the NiMH).
I had this bookmarked when I bought mine (2016): "There is a NiMH battery pack that provides 201.6-Volts standard on the Two models. There is a 207.2-Volt lithium-ion battery pack standard on the other models. A key difference between the batteries is that the lithium-ion has greater energy density than the NiMH, which means that it can store more energy by volume. That said, the Prius Two Eco model has the greatest estimated fuel economy of all of the vehicles: 58 city/53 highway/56 combined miles per gallon." 2018 figures may be different. I'd be getting the one with the features you want (HUD, RADAR Cruise, Cloth/Leather seats etc).