I am a retired Physician Scientist who briefly raced bikes when I was in medical school. Now that I have free time I have resumed biking 100 miles/week. I decided to upgrade my older titanium frame with the SRAM 12 speed eTAP RED equipment. I am extremely satisficed with the results, the derailleurs work flawlessly, haven't missed a shift in over a month of riding. I realize these were made for professionals but I can assure you that the ease of shifting is important for persons my age to ride comfortably and safely. The hydraulic disc brakes work well, especially important for me as I ride a long section of downhill requiring brakes to keep my speed under 25 mph. I think the 12 speed cassette and the Red chain rings with new 12 speed chain are an important part of the extremely well functioning unit. The closely spaced gears contribute to the smooth shifting operation.