What is similar to Side by Side?

What is similar to side by side 1-4?

If you had to select a course book that is as good as and similar to Side by Side which set of books would you select?

I am already using Side by Side but I am preparing to open another English school with my Kindergarten boss. We need to use books that are different from those being used by other schools.

Is Streamline any good? I have never used it and would like to know your opinions.