I've got 25k on my 2011 Kia Optima 2.0T. Some minor issues between 11K and 16K that the dealer took care of appropriately, and running great now. I'm very satisfied with it, spent $10-20K less than other cars I was considering, and have a 10 yr/100K warranty. My dealer (notably not where I purchased) has been great the few times I've needed them.
The hybrid version has had some teething problems, however.
To the OP: I would change the FF sooner (maybe 3.5K miles), then stick to the recommended OCI, and definitely use the OEM filters. They're excellent, not expensive, and Hyundai/Kia are sticklers about that.
BTW, many of the Optima and Sorento are built in Georgia now.