First of all, as we've already noted, the Jetta is bigger than before — 1.3 inches in extra wheelbase to be precise. That's saying a lot since the Jetta was already on the north side of lengthy and a far cry from the pert little compact that dawned at the turn of the century. Indeed, at 6-foot-3, I could pretty much sit "behind myself" in the Jetta, with more than enough legroom front and back. That's actually pretty astonishing for a "compact" sedan. (Back in the 2000 Jetta, I'd have had to saw my legs off to fit behind myself — and I'd know, I owned one). That should be particularly appealing to families looking for a new, inexpensive car with a huge back seat for teenagers or rear-facing child seats (and I suppose my college buddies would've been much happier).
Now, should you have a forward-facing seat, note that the new head restraints are rather tall. That may be great for grown-ups, but the restraints are fixed, which should make it harder to attach a child seat to the latch point atop the parcel shelf.
As for the trunk, it's once again very wide, very deep and generally enormous. Some won't like the free-flying gooseneck hinges, which are one of the Jetta's many cost-cutting areas relative past versions.
In terms of design, I think Volkswagen did a good job snazzying up the Jetta from its rather dreary predecessor. There's more than a whiff of Mazda 6 present and maybe even a little of its Seat VW corporate cousin, but in any event it looks much better. Materials are also a step up, but that's perhaps saying more about the old car, which came to market with rock-hard plastics on all but the priciest trims. We only had access to an SEL and R-Line, though, so maybe that's still the case.
The dash top is reasonably soft to the touch, and as is customary these days, features stitching. The front door tops are equally soft, but the rears are hard plastic as is the parcel shelf (which was carpeted on the Gen IV and V Jettas). To be fair, that's certainly par for the compact-car course these days, as is the rest of the cabin's quality, really. As such, I'm not sure this new Jetta is any more premium than a Honda Civic or Mazda 3, if it is even their equal. Once upon a time, the Jetta was nicer than the average compact sedan — today, it's bigger than them.
All of the switchgear is excellent VW parts-bin stuff, and in terms of tech, you'll note in the above photo gallery the two different touchscreens and instrument panels. The one with the smaller touchscreen and conventional gauges is in the R-Line and lower trim levels. The larger, fancier touchscreen, its surrounding touch-operated controls and the Digital Cockpit all-display instrument panel comes on the SEL and SEL Premium. Apple CarPlay and Android Auto are included with that and are available on other trims.
So in total, the 2019 Volkswagen Jetta does indeed have a more stylish and premium cabin than it replaces. That's definitely a welcome advancement. Did it need to get bigger, though? Apparently focus groups and the like thought so, but this new Jetta is definitely stretching the definition of "compact car."