I imagine you refer to the seminary in Israel. I know people from both schools, though. 🙂
It’s not quite a BY, but the girls I know who went there came out very frum. Then again, they went to Israel with the intention that they would become frummer.
There is a large mix of girls, a lot of hashkafah, you don’t need to have strong Hebrew skills. That’s pretty much all I know about it.
I don’t know anything about the seminary, but the sefer is great. Google “tomer devorah” filetype:pdf and you’ll go right to it. The sefer, a classic work of (pre Mussar-movement) mussar by Ramak, is a beautiful guide to emulating Hashem’s traits. Everyone should learn it at least once.