Hi and welcome to the Forum!
You're English is just fine, better than some of us are able to write it.
and certainly better than my German!
Of course you'll have to do your own rating on the performance of the Diesel because we just do not have it available to us in the US to the dismay of many. Please give US your feed back on that if you would!
The quality, as viewed by the owners, appears to be very good. The fit and finish seems to be better than most with very few problems reported. Little things seem to come up in discussion on just a few items like the cover over the spare tire sometimes rattles, door adjustment including the rear hatch, window track adjustment and a few have had issues with the lack of power (below normal) when pulling out into traffic on slippery roads. This last problem that I just mentioned is maybe caused by programming of the ESP and the factory is looking in to it. The thread:
may give you our thoughts on things that just bother us but not necessarily considered quality issues. I don't recall too many across the board issues, only isolated problems. Overall I give mine VERY high ratings.