I haven't had any issues at all with my one, but then I've only had it for a few months, though it does get used every day - and this is the problem!
Every day I do a shortish journey, not long enough for the car to get up to proper operating temperature, and this apparently is one of the causes of dpf issues. There are ways of getting around this i.e removing the dpf (pretty obvious) but it's something I personally wouldn't do just in case there were any warranty issues.
Another thing - these 335d's are not that brilliant with fuel consumption (well, let's say my one isn't) I never get more than around 25-29 mpg unless on a long run, although this should be expected, they are 3 litre twin turbo's after all.
Hope this helps (a bit).