2012 Hyundai Sonata 2.0T.
I rent cars a lot, usually for few weeks to a month at a time, so I can easily compare different cars as I rent them.
I rented a 2012 Sonata for a week, and did over 1500 miles with it, about 50-50 city/highway. I was considering buying a Sonata, so this experience came in very handy.
The first impression was OK, although the car felt slightly underpowered right away. A couple of months ago I rented a VW Tiguan. I was really surprised with its power, speed and decent mpg; since the Tiguan is also powered by a 2.0 turbo, engine, I was hoping for similar performance from Sonata. But that was not the case. The Sonata felt very "large family car lazy".
If you think that this lack of performance was a compromise to achieve better MPG, you're mistaken: the Sonata disappoints there too, and real time MPG shows absolutely abysmal numbers around town, and pretty bad numbers on the highway. This engine seems to be tuned to give wonderful MPG numbers at one sweet spot, at a cost of horrible MPG in all other situations. With Sonata, the sweet spot for good MPG is 60-70 mph, at around 1900rpm, on level terrain. Everything else makes the mileage drop to below 20-25mpg, and if you are pushing it, as in driving aggressively, your mileage will be destroyed. Of all cars I ever rented, and there are many of those, Sonata ranks as bad as Fords and GMs in MPG department, which is nowhere near as good as their Japanese or European counterparts.
Funny enough, due to that feeling of lack of power, and the size of Sonata, I thought that it must be its weight that is making it so sluggish; after all, it is a larger vehicle than Tiguan, even if it is not an SUV. Then I compared the curb weight of VW Tiguan and Sonata, and found out that Sonata is 150-200 lbs lighter, while it feels about 500 lbs heavier.
Sonata's interior is OK, although the radio and buttons around it are far from intuitive. To the right of the steering wheel is an edge of the center console, which cut right into my kneecap as I was driving - very uncomfortable. It was obvious that no one of my size (I am 6' 4") ever tested this interior while it was being designed. The steering wheel controls for phone are badly positioned, so I pushed them inadvertently more than once.
Bluetooth connectivity worked OK for the most part, but I missed the Tiguan's Bluetooth. The Sonata's Bluetooth was also a lot less intuitive to setup, as was its radio. I never found fader settings for instance.
Seats are quite comfortable, which is a big plus, and the car is really big, yet it handles well. The amount of stuff that can fit in the trunk is amazing.
As I drove the car, things similar to inexcusably bad MPG, and not-so-friendly radio or center console kept popping up and telling me that this is not a car to buy. And truly, those things that I quickly learned to hate about it proved to be very frustrating. For instance, the right rear blind spot is large enough to fit an entire small car in it. I was very nervous every time I needed to change lane to the right. The left blind spot is actually better in that respect.
Another thing that drove me nuts was driver's door, which kept coming back at me every time I opened it up - it would simply bounce back at my legs, trying to break them, no matter how carefully I opened them.
The last point that increased frustration with Sonata was the trunk release: one needs to hold the trunk release button on the remote for full three seconds to open the trunk. Try holding a bunch of grocery bags, and count slooooooowly "One-thousand-and-one, one thousand-and-two, one-thousands-and-three... one-thousand-and-four... one-thousand-and-five...???#$&^%@#" and then you realize that for whatever reason, it did not work. Release the button and press again, and count again, hoping it would work this time.
While the Sonata is a decent car overall, to me the biggest problems, in order of their importance were: slow delivery of power, especially when passing or accelerating; terrible gas mileage; knee pain from the sharp edge of the center console; less than user friendly interface with radio, trunk, revengeful driver's door and so on.
I also noticed that while driving straight on the highway, the steering wheel resisted my input too much; I cannot quite explain it, but it seems that the car is very sensitive to the road being not level (which it never is), and starts pulling to one side, and correcting that becomes exhausting very quickly. Other cars will also pull to the side when on a road which is not level, but correcting for that will not be met with so much resistance as in the Sonata.
One last bit that kinda put me over the top on disliking this car: I was at Chevron gas station, rushing as I needed to return the car within minutes, and the pump stopped pumping with more than half the tank left to fill. I tried again, but it stopped immediately. I kept trying, and every time I would get about 1/4 to 1/2 a gallon in, and then the pump would stop. I moved to a different pump just to try again, but I got the exact same problem. Other people were filling up and leaving, I was the only one struggling as Sonata refused to be filled up. Finally I gave up, and returned the car not quite full, as it was taking only about 1/4 to 1/2 of a gallon at a time before it would cut off. (quick search on the net reveals this is not an isolated incident with a Hyundai vehicle; however, it was the first for me, and I drove hundreds of different cars).
I had three different receipts at the rental car counter as a proof that I tried to fill the car up... but the stress, added footwork both at the Chevron station and at the rental car counter made me hate Sonata with passion. The way the pump handle fits inside the gas tank opening is a little weird on Sonata, as it seems that it is too low, or not tilted in enough, hence I think that it is the design problem. I filled at that same gas station million times before as it is close to where I live and it NEVER gave me that problem. I also never observed anyone else having the same problem. All in all, I discovered yet another design issue with Sonata. One has to wonder how many more issues I would have discovered had I kept the car longer?
Actually I just remembered that there was one other issue, which was kinda strange: when high-beam lights were ON, they did not seem that bright or "high". Usually, when one turns on the high beam lights, they light up the entire highway, and you can read signs which are far away, easily. But with Sonata, it seemed to me that high beam lights were just low beams with slightly more power - they did not reach far at all, and there was no "blast them" effect which is so common on all other cars.
Even if all these smaller issues were improved, I would still have to pass on Sonata, as it is slow in acceleration, and bad on MPG. From the moment I step on the gas pedal, until I see the car accelerating, it feels like an eternity. I am not even convinced that it is due to turbo lag, it felt more like the whole combo of turbo-transmission-chip are really slow. Once it does pick up on my input, it starts moving nicely, albeit at a great price at the pump.
In conclusion, good cars grow on you the more you drive them, while my experience with Sonata was progressively more frustrating the longer I drove it.