I have been on the Sandoz 50 fentanyl patches for the past 5 yrs and they have worked great. When I got my refill the other day, everything was different. They no longer had the resevoir design. When I first tried the patch, I was given the Mylan generic brand with the matrixdelivery system. They did not work AT ALL!! SO, I was wondering if anyone had tried the Sandoz with it's new deliver system?? How do they compare to the Duragesic brand with the matrix delivery sysem?