Grisar
453
cal 240
I like 240 for the following reasons:
240 is so far, based on my personal experience, the most reliable Patek's automatic movement (among 315, 330, 324, 240).
Winding efficiency is very good. (even many claim that 240 is due to the size of rotor inefficient)
Elegant and beautiful layout.
Thin as a whole, very thin bridges. (This is a big challenge for surface decoration and general reliability of the movement.)
Simple construction. (I am convinced the simplest construction is the best construction for mechanical devices.)
I have no problem for Patek to continue to use this base movement for further complications. I agree, however, it would be more suitable for Patek to create more exclusive movements for very high-end complications such as 5102.