Master 628 and 793 movements are well-known brands of Longines, and both movements have good shock-proof function. However, the dial of the 793 movement is larger and more valuable. From the design point of view, the 793 movement is also more beautiful and practical than the 628 movement.
Generally speaking, Longines 793 movement has better value preservation than Longines 628 movement. However, the specific degree of preservation depends on many factors, including the rarity of the movement, market demand, maintenance status and so on. If you want to know more detailed information, it is recommended to consult a professional Longines watch appraiser or auction house.