I'm still pre-op (11 weeks, Mr. Limpy. Make your peace...), but have been full time for a while. As far as anyone else is concerned, if they ask me, I am a woman. If they press, they get my "I am a human being" speech, in which they get a pretty good picture of what bigotry really looks like (check the mirror...).
I WILL declare in public that I am a transgender person, particularly when I am making a point in a public forum. I recently declared on an open mike in front of a couple hundred people that I am a transgender veteran, for example, to remind a congressperson that we exist and are constituents with a support base (an upcoming bill may impact trans folks in military service).
I am definitely not stealth, and am pretty easy to read, but I seek to use that to our mutual advantage. Around me, every day is the Transgender Day of Visibility.

I do not normally advertise my transgender nature when out in public, and do seek to pass at casual inspection. That's a basic safety issue.
I would love to get FFS someday and have passing privilege. Being followed around at a mall by a screaming religious fundamentalist is Not Fun. I'm not there yet, and I may be forced onto a federal government medical program when I turn 65, before I can get to the front of the queue for FFS, which would put insurance coverage at risk and force me to pay the full price. (Going overseas would be an option then, but that puts me at the back of another queue.

)
Even with full passing privilege, or perhaps even because of full passing privilege, I would still be out for purposes of promoting our need for safety, legal protection, and support against a hostile transphobic culture. I can't bring myself to consider "I've got mine! So long!" as a reasonable path for me, personally. That's just how I am.