I think the main difference between seminaries, as well as yeshivas, is this. In strong places, the teachers are people who have themselves spent several years sitting and learning Torah seriously. They have spent time interacting with other serious talmidei chachamim, learning from and interacting with them. Some of these serious people decide that they want to spend their lives teaching others, and thankfully they have tremendous experience on which to draw and teach, since they have spent many years learning first. They know chumash and midrashim, mishna (and gemarah), halacha and hashkafah, because they have spent years seriously studying these things.
At weaker places, most of the teachers are people that may have spent a year in seminary, but then spent very little time seriously learning Torah before starting to teach. From what I’ve heard DB is a really wonderful sem, but I am looking through their list of teachers online, and with very few exceptions, most of these teachers did not spend any serious amount of time learning themselves. Maybe they went to law school, or got a masters in teaching or social work, or even in Jewish education, but these are not people that have spent a significant number of years actually learning. Of course they must know something to teach, and they probably speak very nicely, are smart, organized, and “inspiring”, but you won’t get the same depth, generally speaking, that you’ll find in places who exclusively, or mostly, hire people who have been learning first for many years.
Consider this difference. You’re learning hlichose shabbos. A teacher in one sem is a person who learned the basics of hilchose shabbos in yeshiva or seminar. He/she knows the basics of borer, or mlaben, etc and teaches you the information in an organized manner. They can answer basic questions and their class leaves you educated and informed. When you have a question they look it up in the lamed tes melachose book and get back to you first thing tomorrow.
Now, consider another teacher, who doesn’t just know hilchose shabbos, but really knows hilchose shabbos. They were fortunate that when in yeshiva they learned it b’iyun, and still remember the important sugyas in shabbos, eiruvin, and throughout shas. They learned the mechaber and Tur, the magen avraham, and the other poskim. They feel comfortable picking up not just a shmiras shabbas khilchasa, but also tshuvose of r’ moshe feinstein and r’ shlomo zalman. They understand the nuances that can only be appreciated through broad experience, and have the ability to look back at the Rambam and the Milchamose, the gemaras, yerushalmis, the yam shel shlomo’s, etc.
Learning from these two teachers are two different types of experiences. I imagine that some places will provide mostly teachers in the former model, while a few very solid places will provide teachers of the second model. Migdal Oz is one extremely strong “MO” place that certainly provides teachers of the second type, and which I can’t recommend highly enough. I have heard good things about Midreshet Lindenbaum, but don’t know much about it. Michlalah probably has a mix, but certainly many teachers of the second kind.
Having teachers of the first or second kind does not mean that a place is better or worse. Many families are perfectly happy with teachers of the first kind, if they are warm and “inspiring”, and can help infuse a sense of meaning and worth in their daughters, and that’s very important. Many young women attending sems are looking to form connections with teachers and other students, and of course that has little to do with what kind of teachers they have.
Good luck with your applications!! May HKB”H help direct you to a place that is perfect for you.