Well, it has been a few months now, and many sessions go well into 15 or 20 hours.
The one thing I can say though, is that everytime I go to the costumer's car, he has a smile in his/her face; bass, mids, highs, voice placement and instrument imaging and details are at a level now, that I could have not possibly match with my old Mackies Hr 824s, or the Genelecs 8050s, or the YSM1s.
In one of my last projects, the client used 3 different studios;
at mastering we were all at Phaze One here in Mississauga [one of the largest and most expensive studios around, and also where GM had a session a few months ago]. The mastering Engineer did some processing on the other two studios' songs [bass, highs, compression, etc] but did not touch my 3 songs.
Adam's 2.5A was one of the better investements I did in my studio. The other one purchase I made 2 years ago, that was also excellent, after 10 pairs of headphones, was the Senheizers HD 600.