Each One in His Camp and His Nusach

"לצבאתם דגלו על ואיש מחנהו על איש ישראל בני וחנו" (נב א)

The Shelah Hakadosh cites the Arizal that just like in the desert, Am Yisrael were divided to four degalim, likewise in Am Yisrael there are four nuscha’os of tefillah and different customs: Sephard, Ashkenaz, Catalonia and Italy, and each person should adhere to the ways of his forbears – "ish al machaneihu v’ish al diglo."

Harav Meir Shapiro of Lublin was known to have said: At the beginning of davening there are various minhagim. Some say Baruch She’amar before Hodu, and some do it the other way around, but everyone together thanks and praises Hashem in Yehi Kevod Hashem L’Olam.

Shelah Derech Chaim Tochechas Mussar 35; Ta’am Veda’as, Bamidbar 2 2