A DE razor holds a blade bewteen 2 pieces of metal. Screwing these together flexes the blade. This flex would seem to be a consistent flex. How then are different blade holders (i.e.: razors) any different from each other? Is it just the quality of the build (i.e.: the threads are well made, the handle is well balanced, etc..)? I have a Parker 13r and I find it....well, it's my only razor, so I don't have anything to compare it to. Educate me, please (and I'll do more searches too).