I changed my DSG fluid on Friday at 121k miles, nothing unusual. Shifts now are super smooth. Last car ('06 Jetta) needed a mechatronic at 185k and is going strong at 235k miles.
Our DSG has been smooth, reliable, and predictable since new. I did the DSG service myself at 40K, now at 60K. Since we'll be doing the buyback next year, will probably not do another service. I don't see how it could matter— the old oil I drained from the DSG was a bit darker than the new stuff, but still completely clear. OTOH, we put about 75% highway miles on the car and, being septuagenarians, don't exactly drive it "like we stole it."
NB: There's a thread in here somewhere that can be looked up, guy claimed the DSG in his Jetta wasn't serviced until 180K, oil came out looking OK, and that he was still driving on at 120K. (I am neither saying this is true, nor do it recommend it in the least.)