You're welcome
Both are connected with the same size quick disconnects so there's no difference as far as that's concerned. There's some cosmetic difference - Seimitsus are a little less convex/more flat, especially the snap-ins which, from memory, are a little flatter even than the screw-ins. I guess there's a slight difference in feel because of this too. Where the screw-ins are concerned the nuts are different but the same diameter and thread pitch so you can use Sanwa nuts on Seimitsu buttons and vice versa.
The main difference is the feel. Sanwas are a good deal more sensitive than Seimitsus and you feel very little resistance when you press them - you don't have to press them far for the switch to activate. I'm guessing just from feel alone that the activation distance, for want of a better phrase, is slightly greater with Seimitsus.
I don't know all the precise data with regards to activation distance, pressure etc - that's just getting silly imo - but the best way is to try them and see which ones you prefer
Did your panel come with Seimitsu or Sanwa buttons?
