In nusach Sefard siddurim, there are pronounced differences between nearly every one, each reflecting the particular view of its author as to how to properly reconcile the Arizal with nusach Ashkenaz.
A significant group of differences, for example, are variances in text reflected in most of the brochos of the Shemoneh Esreh. Even the Artscroll Sefard siddur accommodates many of these differences.
Similarly, some Sefard siddurim have radically different forms of tachanun - some match Ashkenaz almost exactly while others are entirely according to the Arizal.
Are there similar differences between different siddurim in other nusachos, or are all Ashkenaz siddurim essentially the same, all Mizrachi siddurim essentially the same, and so on?