 I am very pleased with my purchase of a certified pre-owned Sonata Hybrid.  I have had it for over a month now and have taken it on several trips.  I had initial concern with the trunk space, since the seats don't fold down because of the batteries, but found that there was plenty of space for our items.  I have been getting great gas mileage for a mid size sedan.  On my highway trips, I am averaging 44.5 miles per gallon and overall around 38.5.  The ride is smooth and acceleration is great.  When quickly accelerating to merge both the engine and the electric motor will assist the car to get up to speed.  I also like that the electric motor will assist or take over when holding speed on the highway, even at 70 mile per hour.  Thus the increase in gas mileage on the highway.  Love the car so far and hope to own it for a long time.