We have had our 2011 Elantra for about 1.5 years. We have about 28K on the car and have had no problems whatsoever. I regularly get 35 mpg in mixed driving and get 40 mpg in highway only driving.
We got the navigation and it works very well.
Its a fun little car that is great for commuting!
Navigation, XM radio, gas mileage.
The only things I would improve on the car are the seat cloth because it seems to absorb stains easily.
Change the material of the back cover behind the back seats and console between front seats as they look too plasticy.