Heard/read that those hybrids get worse gas mileage when running the gas engine - they factor in the total MPG with the electric motor ... not fair ....
The gas engine is a small block 4 cylinder engine. In my Camry, the gas engine works with the electric as determined by the needs of the vehicle. Driving on the highway is what some refer to as “pulse and coast”. At highway speeds the electric kicks in to assist the gas when more power is needed. The gas is about 155 hp and the electric is 40 with a lot of torque. What you see on the flats and downhills is the gas engine will idle to maintain speed (works out to 60 MPG). On long trips from western Ohio to Duluth, MN, or State College, PA, Bristol, VA I have gotten around 41 MPG. In town I get about 33-34 as advertized. Sometimes better depending on timing the lights and in areas where there is no traffic. I am very happy with the Camry Hybrid.
Toyota and Nissan share technology so the Toyota Hybrid Synergy technology is married up to a Nissan continuously variable tranny. That means the Toyota Camry Hybrid and the Nissan Altima Hybrid are basically cousins where the only difference is the 4 cylinder gas motor and the battery supplier. Note you still need a normal car battery for the gas motor in the hybrid. The Nissan has better acceleration, I’m told, but when I bought mine they weren’t selling the Altima Hybrid outside of New Yalk and Cal-e-fornia. The Camry is made in Kentucky.