No reason to stay away from sects that have no living Rebbe. Breslev has done wonders for BT’s in Israel. It still has leadership that follows the same trend as Litvish leadership as opposed to being decided by family dynasty. When I say Breslev, I’m not talking about the Na Nachs. There are plenty of Breslevers just as legitimate as any Chassidim, they just happen to not have a living dynasty. I would recommend Breslev if you were in Israel, in the US I think that would be a bit tougher. I suspect 147’s comment about 0 Rebbes was a thinly veiled dig at a different, well-known Chassidus that will remain unnamed by those of us who actually have some respect.
I think this decision should always be based on which Chassidus you like learning best. And if you don’t know Yiddish, that probably eliminates more than half of them.