There are two basic types of blades: stainless steel and carbon blades.
When it comes to choosing which blade is best, you’re comparing strength versus longevity. Both do an effective job, but the stainless is a little less hard and more brittle, which means it’s more prone to chipping edges. However, the stainless steel blade will not rust.
On the other hand, the carbon steel blade is stronger than the stainless blade, but has a much more limited lifespan. You typically can only get one day out of a carbon blade before it rusts over. You don’t want to leave it in the scraper after use because it will corrode the track and make it more difficult to open and swap out the blades. The carbon blade will even rust just from sitting around over time. Remember, rust can also lead to scratches.