As a student and teacher of Zen, I find myself making a common mistake that many people do when referring to Zen--assuming that there is ONE kind of Zen. There isn't. One of the most powerful myths that exist about Zen Buddhism is that there is a normative standard, as if all Zen school and practitioners agree on one set of principles.
Zen (including Seon and Chan) is a blanket term that is completely conventional, provisional, and conceptual. In other words, Zen itself is empty of having any sort of essence. Ironically, despite emptiness (sunyata) being such a central tenet of (many schools of) Buddhism, Zen Buddhists often subscribe to the myth that there one single entity called "Zen." Which as history would have it, in the West is more often not Japanese.
Actually, there is very little consensus about what Zen is. Despite Zen's etymological connection to the Sanskrit word dhyana, meaning meditation, not all Zen schools emphasize meditation to the same degree. For example, zazen or seated meditation, represents the sommum bonum of practice for the Japanese Soto school; whereas in other sects, meditation may take a more peripheral role next to koan, hua-tou, chanting, or mindfulness practice.
My point is, there is no single Zen. Although it is very difficult to have a conversation about Zen if we constantly have to insert, "Well some Zen schools believe...," we need to be cognizant of assuming that we have the authentic Zen.
Western Zen--and this is based entirely on my personal experience, and thus is merely an opinion--tends to be elitist. Zen practitioners, subscribing to Bodhidharma's quasi-mythical maxim that Zen is beyond words (and thus connotatively reserved for the spiritual elite), like their Zen a certain way. Too much Mahayana Buddhist liturgy or study and Zen loses its bare-bones flavor. Too much chanting or bowing or reciting the Buddha's name and--gasp!--Zen "degenerates" into pan-Buddhism and is no longer "Zen," whatever that means. Not enough emphasis on form and Zen appears loosey-goosey.
For instance, Korean Seon is much more ecumenical than Japanese Zen. It has a much broader range of practices and doesn't subscribe to such a narrow self-definition of identity. The same applies for early Chan monks who practiced right beside students of Hua-yen and T'ien-T'ai because the idea that "I'm a Chan monk and therefore..." didn't exist then. It had not yet developed. Which suggests an important point:
Zen developed over centuries. It didn't appear fully formed in its current state. Contemporary Zen is the result of hundreds of years' worth of political, social, religious conditions and factors all playing off one another.
This is very humbling and informative. My concern as a Western Zen Buddhist teacher is how this impacts our practice and lives. Humans are prone to appropriating any idea and incorporating it into their identity, or sense of self. After a time, students may find themselves saying or thinking, "I'm a Zen Buddhist; therefore, I practice [such and such] exclusively."
Frankly, that's unnecessary. If we take out all of the superfluous verbiage from that statement, all we are left with is "practice"--whatever form that may take. For me, it's a constant return to the empty, clear awareness of "Don't know" mind. From there, we then ask, "How may I help you?" I won't presume to say that this is THE Zen practice, because it isn't. That's a huge assumption, arguably narrow-minded, elitist, and most importantly, not very helpful.
To avoid ending on a negative note, I'll conclude by paraphrasing one of my favorite instructions of Zen Master Seung Sahn: "Practice, practice, practice, for 10,000 years. Reach enlightenment and then save all sentient beings!"