Your question is very open-ended and explosive.
My opinioin about Lubavitch is ccomplicated. I am very into their Chassidishe Torah; I own most of the maamarim from the first three Lubavitcher Rebbes, and the ones i’m missing are mostly because they need to be reprinted. There’s no Chassidus/Kaballah that i’ve found as deep as theirs, and it’s wonderful.
That being said, the modern day Lubavitchers have taken a wonderful Tzaddik and completely tarnished his legacy. Most Lubavitchers believe that a dead man is Moshiach, which is apikorsus; the ones that don’t believe this are, by and large, afraid to speak up. They do some awesome work in Kiruv, in places that nobody else goes, which is wonderful But their approach has irrevocably changed the entire feel of the Chassidus, and you have to search hard to find people who truly understand the Ba’al HaTanya’s Torah, let alone incorporate it into their daily lives.