Robert McLune:
My understanding is that Zen is within the Mahayana "branch", correct? Now so far the only place I've been able to find in which to practice with others is a local Zen center. I quite like it, and the rituals and stuff, but again it's nothing like what gets discussed on DhO. For one thing, I wouldn't want to overstress the "with others" in the above! Sure, we all sit in the same room, but there's very little other connection. Once, during a rare discussion session where people were talking about themselves, I was talking about my practice but it was as if I'd said something naughty. Most people were talking about their anxieties, or their childhood experiences. Kinda like a shared therapy session.
Yes, Zen is a major tradition within the Mahayana. There's a lot of variation in Zen, and no two centers are going to be the same, so I'm not sure how much I can comment on the one that you've visited. But I suppose I can say some things from my own experience (I live at a Zen center).
First of all, I don't think you can get a real feel for the Sangha until you've been with them for a while. In Zen especially, relationships within the community tend to grow very organically and subtly. Just sitting with people for long periods of time can establish a connection that transcends words - it sounds wooey and "spiritual", I know, but it's actually a very palpable and utterly profound thing when you experience it. It's definitely not like the community you'll find on this or any other internet forum.
As for people talking about their own psychology more than their practice: Zen methods tend to be very direct, intuitive, and harsh, and can therefore mobilise the unconscious to a degree that other practices may not. As such, psychological openness is a very important and fruitful facet of Western Zen practice. We also don't tend to discuss our own practice outside of the dokusan room, at least in very practical terms. This is also important because the teacher-student relationship is a crucial element in the way we practice and is also tailored for each individual specifically, and it can be thus unhelpful to compare notes with others who are working in a different context.
I don't have a teacher (yet), but if I picked someone from the Zen tradition is it likely I'd find their approach at odds with MCTB? One small example. When I sit, I'm not too concerned about whether my eyes are closed or open -- if I had to pick I'd go for closed. Also, I'm trying to do the noting thing I heard about originating (I think) with Mahasi Sayadaw. Both are different from Zen, where they have an "eyes open" approach, and where they count breaths and don't note.
It's true that the Zen approach doesn't appear, on the surface, to have too much in common with MCTB-type practices. Also, the four path attainments are quite different from the way progress and realisation happens in Zen. Nonetheless, you will ultimately traverse the same territory. Also fyi, counting the breath is a preliminary practice to either koan work or shikantaza.
Is Zen a sub-optimal choice? Or are there perhaps, just like Buddhism overall, two Zens?
In my opinion, Zen is the optimal choice! But it really depends on your own trajectory. I would at least give it a good try, though.