You just can't compare one person's mpg directly with another's unless they're doing the exact same route at the same time of the day.
I use my Polo GTI (2.0TSI 200ps DSG) more than my Golf R now, and with the same driving style, my mpg can vary greatly on my commute. On a normal school day morning, dropping the kids off at breakfast club for 0730 and then driving 13 miles to work on mixed roads, with some bits highly congested, over 30-35 mins, I average 35mpg most days. More congestion coming home and it can be as low as 30mpg. During school holidays with fewer cars on the road, I get 37-39mpg on the same Journey.
If you do short journeys, your mpg will be poor.
If you drive in congestion with less than 20mph average trip speed, your mpg will be poor.
If you have a poor driving style, your mpg will take a hit.
2 or 3 of those factors together and your mpg will be atrocious.
I can score 96/100 on thinkblue trainer and still only get 30mpg - good driving technique cannot save you from the effects of congestion or short journeys on mpg.
Maintaining 80mph on the motorway for a 100 mile journey in the Polo will get me 43mpg, more like 47mpg sticking to 70, in a fully occupied car. Some things are just out of your control.
If I was doing 5 miles in city centre stop-start traffic every day I'd feel lucky to crack 20mpg.
In urban traffic, my low geared R is as economical as the Polo GTI. On the motorway, the R does 35mpg at 80mph as opposed to 43 in the Polo. Just goes to show that in urban traffic, both cars perform poorly.
If I were doing 20 miles each way on my commute, holding a steady 60mph on uncontested roads, i'd be in the high 40s for mpg.