This is my wife's Hyundai i45 and I'm not allowed to drive it too often unless it's to put petrol in or she's too tired on a country trip.
We brought it as a demo unit with about 5000K's so the price was right otherwise I would not have bought it (maybe the spectacular styling might have won me over). It's been very reliable and the service costs are OK and if you bleat about being a pensioner they usually see sense at the dealers.
Fuel economy is great on a trip often dropping into the 7's but lately around town SWMBO is managing to get on the wrong side of 13. The car has now done 73,000K's and need's 1/2 a litre of oil every few months. 2 of the tyres are original as are the brakes.
We have had a few issues with parts of the glass roof trim lifting and the gear shift paddles stopped working (not that we ever used them). The auto transmission is excellent and changes smoothly and on cue.
The car is very comfortable on a trip and when allowed to I enjoy driving it on the open road. I don't like driving it around town as I always get the feeling the front end is loosely connected to the steering with a lump of soft rubber.
Ride can be a bit harsh at times probably due to the low profile tyres. Would I replace it with the new Sonata (read I45)? Yes, with the mid spec model and only if the new car feels a lot better to drive around town and I can get a good deal.