The Jetta has always been a half-assed Golf/Rabbit. Same basic chassis and all, less cargo space, and often gets too fancy for it’s own good and sacrifices longevity and reliability in the process.
If you want an upscale interior, redecorate your living room. I actually prefer cloth seats over leather, and many of the things that other people consider to add class to an interior are things that either break quickly and/or look like shit after not too long. Do you plan to ditch this car 2–3 years down the road, or do you plan to actually keep it long enough to pay it off? What is cool now may not be cool later, so think about how the car will age. Think about durability.
Stock sound systems were meant to be replaced by anybody who cares about sound, and can often be done for less than what the car dealer charges for the better stereo.
Given that you are looking at these two, I am under the impression that you are more about style and/or comfort than anything else, so I would save your money and look for a certified pre-owned BMW or Mercedes Benz. If I am wrong and you actually care about performance, look towards Mazda and Nissan. All have build quality, and I honestly think VW jumped the shark there about twenty years ago. As much as I love the A2 Golf and classic Beetle, I don’t trust any VW made after about 1992; they seem to have forgotten how to make a reliable electrical system. And when it comes to cool, a “hot hatch” will beat any non-luxury sedan any day of the week. If you want to a cool sedan, you need a luxury brand name, and VW pales in comparison to BMW or MB… or even their sister, Audi.
If you are stuck on VW then go with the GTI. If not, tell me what you really want and I will do my best to help you find the best car for those desires.