I have owned several Japanese nameplates, bought this at model year end as a demo, was $8K below sticker with 4K miles. It's completely loaded except for GPS and rear spoiler.
I'm very pleased with my Sonata. It's been perfectly reliable and is still tight at 70K miles. It gets very good gas mileage (in excess of 30 on trips - I've seen 33 at times - and I'm not lightfooted). It's a great highway car that handles well at all speeds - very controllable and stable.
Performance is very good for a 4 cylinder, though like all 4s, it does shift more often than larger engines, which is only mildly annoying. Some downshifts are pretty sudden but acceleration is impressive, even at higher speeds. It is touchy from a standing stop at times and "jumps" quickly now and then.
It's very comfortable and quiet and is classy looking. Now and then someone thinks it's an Audi, which isn't bad company. In some ways, I prefer this body style to the current one.
Will I buy another one? Not sure. The price advantage over the Toyota Camry is smaller now, plus Toyota has matched Hyundai's warranty. My wife's 2012 Camry LE is a very impressive car, though I have not driven later Sonatas.