I think Jetta competes for buyers who think Camry/Altima are too large and unnecessary. Such other cars vying for similar buyers might be the CSX, S40, G6, TSX, Legacy, 9-3 (a bit more upscale), and maybe to some extent the Fusion, Mazda6, and Accord. The Passat 2.0T goes after Camry intenders as well as the Accord (it's sort larger but not huge to me), S60/V70, 6 Wagon, Legacy GT/Outback, Aura, Azera, Maxima crowd IMO.
IMO new Jetta is priced a good $1,000 too high. City Jetta a bit too low. The gap between them, and Rabbit-new Jetta too large.