I just used a new Merkur Super blade for my second DE shave ever (used a Derby Extra my first time). My neck feels like someone took a rake and grinded it back and forth on my neck! I rubbed "my nick is sealed" on about 15 nicks on my neck and even in the places where there was no blood it still stung like hell. I put the used Derby Extra back in and it was shaving without any problems! Are the Merkur Super blades duller than Derby Extra's? Also, is there a list somewhere that show's the blade sharpness from sharp to sharpest? Thanks!!