Fuel Efficient Hatchback - TDI? Prius?

I think the Golf would be the better choice. Better interior, more fun to drive, better looking, etc. If you're only going to keep a car 2-3 years then you're under warranty anyway and you shouldn't have many problems in that time frame.

I have a 2013 Golf TDI Tech....you won't find a better car in its class/type for comfort, quality & economy. It's not unusual to get 40+ mpg.

My only issue with the car is that I am short and I felt like I was sitting in a wash tub after awhile. Before this car, I had several SUV's and did enjoy being able sit up a bit higher. I also am not enamoured with cloth seats.

I only had one mech problem..a fan motor that burned out which was fixed under warranty. DEF is not required or AdBlue as VW calls it. No additional maintenance is required.

Overall, it would fit the bill for what you're looking for.

The 2015 Golf TDI is an excellent car. There's also a wagon coming soon, if you want more space for the dogs.

Among hybrid hatchbacks, the Ford C-MAX drives far better than a Prius. I really enjoyed my week with one (review in the menus below the photo). Reliability has been pretty good so far, and if you'll be trading in 2-3 (or even 4-5) years this shouldn't be much of an issue.

Though not a hybrid, the Mazda3's real-world fuel economy isn't too far below the C-MAX's, and it drives very well.

Any impressions of the latter two?

I don't think the larger wheels will affect the ride much.

The transmission fluid change alone isn't that much. Maybe together with a bunch of other maintenance at the same time. IIRC, VW also calls for a brake fluid change ever three years.