YULA is a centrist Orthodox school and Shalhevet is left-wing Orthodox (about as tolerant and free as you can get for an Orthodox school).
Orthodox sources tell me: "When Shalhevet opened up 15 years ago, YULA had an opportunity to define itself. They could send all the trash to Shalhevet. Instead YULA tries to compete and takes all the same trash shalhevet does. There all these shady persians and israelis that want to feel their kids are frum so they send them there. The dollar is king. The second school is out, the jewishness is out as well in a lot of these families. Shalom Tendler wanted a frum school. The second shalhevet opened, he thought he would finally have it. He fought for 15 years to make yula frummer. Then the whole thing with his nephew Aron happened and he jumped ship and opened up a school that YULA should have been."
I take no sides in these disputes but HaShem’s side and then only on weekends.