Last Shabbat, I had the pleasure of staying with one of my teachers in the yishuv of Tzur Hadassah. Throughout Shabbat I had the opportunity to daven at a mizrachi synagogue who davened nusach edot hamizrach, and an ashkenazi shul who davened nusach ashkenaz. I just wanted to share a couple of observations that I think can be applied to tfillah in general.
First, the general layout is similar, which should not come as a surprise. After davening, I was speaking with one gentleman from the mizrachi synagogue (in Hebrew). He told me that he had been watching my friends and me struggle through the siddur. I explained to him that we were just looking for the correct page. Although I did concede that not being familiar with the siddur itself was a bit of a challenge when the kahal shifted from one section of the davening to another.
Second, despite the lack of familiarity with that particular siddur and nusach, I found it relatively easy to participate. There was a general flow to the davening that I take for granted when I am using nusach ashkenaz. Furthermore, as I mentioned above, since I have a general familiarity with the t'fillah structure, it was less complicated to navigate my way.
The lesson here, I believe, is to strive for a general outline of t'fillah because it opens up our ability to daven in other communities and serves to enhance our understanding of the project of prayer. Finally, really knowing your siddur is key. I like to feel at home in my siddur, although not at the expense of being able to uses others.