We bought this car new in April 2005. It was our third stop after looking at Toyota and Honda sedans. We just were not happy with the interior space or design in either of them. The Sonata's interior is not what I'd call roomy, but it is comfortable and well thought out.
We average 25 - 26 mpg city, 28 - 31 mpg highway.
So far we have found this car to be totally, utterly reliable. We have had zero problems with this car besides the mirror, but still had the peace of mind provided by the free 5 year road hazard program.
Acceleration is good, handling is great, and the auto transmission with the manual shift feature is a LOT of fun. The car also handles winter weather very well.
It is not a fancy, luxurious or super sporty car. It has found a happy medium. I could honestly tell anyone, (already have) that as far as good, sound, and economical transportation goes, you really can't go wrong for the money.