I had recently the V6 Sonata for a car rental.
On the positive side, the car drove well (although not as tight as my Accord) and was comfortable. Plus all of the options can't be beat (leather seats, standard MP3 player climate control).
Now onto the negative side of things..... The interior felt like it was smaller than our Accord, but checking the interior on both cars, the numbers looks the same. The side mirror do not fold. While it may seem a minor issue, on my Accord which do fold, I've had them bent so many times that I won't buy a car without them. The rear window is narrow. While it isn't as bad as say an Impala, I really hate car manufactures that are doing this to cars. It's almost like they want you to get into an accident since you can't see as much from the rear.
As a previous poster mentioned, if you don't have any problems with your Toyota why buy a new car? Save the money and run the car to the ground.
Nick