The 2892 (2892-A2) seems to have been given priority by making it more efficient. Its oscillating weight is better engineered with a larger support for the ball bearing races, which gives it better shock protection. It is almost always finished nicely with perlage and Geneva stripes. This movement is used by many high-end brands. Often, high-end brands like IWC, Girard Perregaux and Frank Muller will assemble the movements in house and replace some of the critical parts from the escapement to the mainspring to gain tighter tolerances