I will only use the SU one now, i have tried so many but Apart from the MS one the groves are just spaced too far apart.
The whole idea of a scoreboard is for immediate scoring, without all the hassle of measuring. The imperial plate of the SU board is the same as MS but gives you the opportunity to add a metric plate and a diagonal one for embellishing or for envelopes, plus a fancy boarder plate. the scoring tool is a proper embossing "ball" tool unlike the little plastic versions which i personally have never got on with. The embossing tool has its own little grove to hold it in place! so you don't lose it
if you have a fiskars paper trimmer, take out the blade and use the groves where the blade would go and using an embossing tool to score your paper/card stock