I previously had a Honda Civic coupe. For a while I had been considering switching to something four door, and possibly hatchback. I could never be the one to drive if more than two people were involved because nobody wanted to get in my back seat (assuming they even could). I also have hobbies (fishing, R/C planes, etc.) that made a hatchback desireable.
Though not a priority, I wasn't against paying a little more for something a bit more upscale. However, I didn't need a luxury car, and certainly didn't want to pay a huge amount.
Despite wanting something with a bit more passenger room, I've always liked the convenience of a small car when driving in the city, parking, etc. I didn't want a new car to be too large. I also have gotten used to not having to worry too much about fuel usage when I drove places because I got 36-38 MPG in my Civic, and I didn't want to lose that if possible. Performance isn't a huge issue, but good handling is highly appreciated, and I obviously prefer whatever I get isn't a total dog.
And along came the 2010 Golf TDI. I haven't looked at the actual specs, but I would be surprised if it was much (if any) bigger in outer dimensions than my Civic was (I wouldn't be shocked if it was shorter), yet it has much more passenger room inside (particularly rear seating). While it doesn't have a huge trunk with the seats up, it is a hatchback which eases loading. And it will accomodate plenty for my needs with the seats folded down.
The Golf TDI has the same HP and similar overall performance stats as my Civic, but has much more torque (over 100 Ft. Lbs. more in fact), so in daily driving it feels as quick without requiring a downsift. It handles respectably as well, while still being smoother and more comfortable on Ohio roads (read: choppy, broken, rough, pot-holed roads).
While I realise this is a matter of opinion, I think my Golf wins hands down in the looks department as well. It's just a good looking car.
While it's not all perfect, overall the Golf's interior is a bit nicer and more upscale as well. And while again, it's not all perfect, the Golf has many more comfort and convenience features vs. my Civic.
Was mileage a factor, sure. As you can tell from the above, it was the total package that interested me. I wanted what the car had to offer. The high MPG rating did help me rationalise the purchase somewhat. So, was improving fuel economy the reason for purchasing a new car? No. Do I have any misconceptions that my purchase was somehow financially wise because I'm getting better fuel economy? No. Did I get virtually everything I wanted in a car, while also getting around 10 MPG better than I was before? Absolutely.