Granted I have a 4.3 (my dad has a 4.4), but after market bars are suited for all types of vehicles and can fit anything with rails on it. That being said, the main difference is A, the amount of weight they can bear (Thule square bars for example can bear a lot of weight), B, the width of the bars (after market can go past edge of rails), C, the amount of wind resistance (OEM have less due to their shape), and D, the shape of the bar (Square, round, airfoil/oval). I have Thule square bars on my 2008 and they are great for ski racks, kayaks, canoes, bikes, etc, however, they are a little noisier and create more resistance due to their shape. My dad has the same ones on his 2015 and he loves them. If I had the factory ones, they would flex more when carrying kayaks and I would not be able to fit my 18' long canoe on top because it would be wider then the width of the bars.
It is a matter of how much use you are looking to get out of them. From what you have described, you want them purely for aesthetics and that "I do stuff" look in which case I would just go for the factory roof racks since they are more sleek and integrated looking, as well as affording you less wind resistance (and better gas mileage). If you want a wider set of bars with more carrying ability with less flex to them, then get an aftermarket. I can take pictures of mine if you would like me to upload some later for your reference. You can kind of see them in one of my albums with the ski racks and fairing mounted on them.
