They're not very good, I owned one for 4 years and did 70k averaging 42mpg, I was glad when I traded it in for my much faster Leon FR 1.4 tsi which averages 35mpg doing the same driving, done 44,000 miles in this so far over 18 months. It doesn't matter what sort of driving you do, the dpf will still fill up and won't clear itself till 45% full. It managed to clear itself in all but the worst of traffic i.e. if it started a regen and you were stuck in stop start traffic for 90 mins you'd get the light. But even doing slow 20 - 30 mph speeds it would regen itself but would take over an hour. If regen started on the motorway it wouldn't take no more than 15-20 mins.
You may want to Google active and passive regeneration if you don't already know, but whatever you do don't take it down the motorway thinking you're clearing the dpf because that's not how it works. The dpf fills up and when it reaches 45% it will then clear itself, it will clear itself by either regenerating passively at speeds above 40 mph ~ or regen actively below 40 mph ~.
If you take it down the motorway and the dpf is below 45% full you will be filling it up and not helping yourself.