I'm not familiar with the stalling problem in the VW. It does have much more power than the Fit.
Among VWs though, the Golf SportWagen is a much better car than the Jetta, and more practical. Too expensive? The 2016s also have a much better infotainment system.
The Fit is more likely to be reliable for years, if you'll be keeping the car a long time. Have you test driven one? A good test drive should indicate whether its highway performance is sufficient for you. I didn't like the buzziness of the engine, but you might not mind it.