What is in the Water Pik system compared to other system? I am trying to get a compatibility.

That's best handled by a Google search. That's not related at all to Costco.

What is that???

You should definitely stick with the other system it's hands-down the best system if there's no system like it

What Wilfredo said - that's not a Costco question. Just Google Water Pik and do your research that way.