From my (albeit limited) experience, a tamper is not a tamper is not a tamper.
The one you got with the SB is useless - it sadly wont even do as a paper weight. And there, lies part of the answer. The best way I can describe the difference between a plastic or aluminium/plastic tamper and the espro or Pullman...hmmm...imagine trying to drive a nail with a block of timber versus a hammer. You might do it, but not do as good a job.
For my money, I prefer te Pullman tamper. Every one is absolutel unique, fits the SB baskets perfectly, and most importantly, do a fine job of compressing the coffee. You will defintely see and taste the difference!