There are two general styles of line cutters. Scissoring type such as Spurs, and saw blade type such as Shaft Shark. I ran Spurs for years and switched to Shaft Shark a few years ago after second time I found Spurs to be in-operable upon haul. Once the collar had slid back rendering the anvil side of the scissor useless. Second time due to bearing failure. To install Spurs requires prop removal and while it can theoretically be done in the water, it's not really easy, especially in murky water.
Studies show the Shaft Shark style work equally well, have no moving parts, and are 2-piece so easy to install in-water. Was enough for me - will not return to Spurs.
Peter