Among bicycle enthusiasts, there are two types of people. Shimano people and SRAM people. The two drivetrain makers have an effective duopoly on mid to high-end bicycle drivetrains. Both manufacturers have their own unique characteristics that separate them. People who work in bike shops are deeply passionate about whichever side they support. I have a coworker who will not show a customer a bike that comes with SRAM components. This same coworker has the SRAM warranty number memorized to make a point of how often it is needed. This coworker loves the smooth shifts of a Shimano drivetrain. SRAM drivetrains have a much quicker much snappier shift. In reference to cars, Shimano shifts feel like a nice automatic. They are smooth seamless shifts. They aren’t the fastest shifts, but they’re smooth. SRAM shifts are like a race sequential. They are abrupt and harsh, but very very fast. SRAM is the racer’s choice. Now I am biased. Every Shimano product that I have owned has broken. This includes my Shimano branded chapstick. Additionally, SRAM chains simply do not break under loads. They withstand abrupt shifts, bad shifts, and all sorts of abuse over thousands of miles. Shimano chains, however, are not as durable. They have a tendency to snap when struck with a rock which is not uncommon in mountain biking. A common criticism of SRAM shifting is that it is not smooth. However, if a rider has a smooth pedal stroke the shifts are smoother. It is my opinion that SRAM is the superior manufacturer because of the speed of shifting. Smoothness is subjective and largely rider dependent.