I've studied with teachers/ sanghas who followed the Elders, and I've studied with some different Zen and Tibetan groups. I agree with a lot of what is said above. The Tibetan and Zen conceptualization of compassion was hard for me to swallow. And the sectarian thing. Although I know historically the Theravadans were not blameless angels in that dispute, most modern practitioners tend to shrug and say "To each their own" (as has already modeled in this thread). From the other side of things, I encounter a lot of strange claims about the Theravada teachings.
"As I am, so are others;
as others are, so am I."
Having thus identified self and others,
harm no one nor have them harmed.
Sutta Nipāta 3.710