I don't know enough specifics, but there's multiple subtypes of serotonin receptors. It's possible that perhaps Sertraline affects different subtypes or a combination. Perhaps the binding affinity is different, but yeah, each of these are different (hence why they're different drugs, and not just generics of the same thing).

I've had a brainzap when I was used MDMA somewhat regularly for a short period in the 90s. It was only once, so it was more a weird "What is this? I feel... something... in my brain?" But I don't think I would want to deal with it happening spontaneously and constantly like withdrawal symptoms present. Sounds awful.

I take Effexor which is an SNRI... From what I've read, is one of the worst in terms of withdrawal (brainzaps and other side-effects). I'm really not liking the idea of me having to someday go off of it, so far for now it keeps me stable, but... if something happened where I would need to go off of it, I'm not looking forward to it.