We just bought this car in late January, so we haven’t put in as many miles as some other folks. Having said that, I have a daily commute averaging 100 miles, so I think I am qualified to write a review on this car by now :) To put it simply, if your objective is to purchase a nice, luxurious family car that is beautiful inside and out and gives excellent gas mileage, then you simply just can’t go wrong with this car. For context, we purchased the Ultra Premium Luxury package with the Mark Levinson audio system. While this car may not be the fastest luxury car out there (spend another $50,000 in change and get a Tesla Model S then), it is a phenomenal grand touring car, no question.
We traded our RX 450 h, which we loved, for a bit better fuel mileage - boy did we get it. Driving home from the dealer, all highway, the car averaged 39 MPG at speeds between 65 and 75. It was smooth, eerily quiet and handled extremely well. If you don't drive it like a race car and accelerate smoothly and hold your speeds nicely, you WILL get the mileage claimed. Others who complain about the mileage do NOT drive that way - we have owned five hybrids and that IS always the case. The complainers never drive the way the car was designed. We also love the lengthened body - it provides a great deal of leg room in the back - our taller, larger passengers love it!
Update: July 2017: I was in an accident and the car was amazing with minimal damages done compared to the amount of force it absorbed. It did surprising well. Had the car fix d with OEM parts and is like brand new. Love this car! Gas mileage is still awesome! I've owned this car for two months now and feel ready to give a review. I traded in my 06 Acura TL. My daily commute is 140 hwy miles round trip (Oakland to Stockton, CA). I drive over two large hill ranges, dare I say, one is mountainous. 98% of my driving is hwy miles and my mileage is amazing. If I drive 70-75 mph, I'll get 39-41mpg, while if I go 65-69 mph, I can get 42 mpg. I've tried just about every way to drive. Easy going, to "really" easy going and in ECO mode gets me the same as in Normal mode. In sport mode and driving really hard I'm getting 34- 35 but again that's fast at every turn, on ramp, and passing other cars.
Bought the 2014 300H 7/2016. In the city, I get 42 to 47 mpg. Highway, it is more like 41-43. Car is very comfortable. Seat vents work great especially in the summer. Heated steering wheel is a welcome addition in the cold mornings.