Surely it means that they know you and your taste. Not a good thing?
But often it sounds like they're insulting your taste.
"It's good, but I don't think you'd like it" kind of makes it sound like it's just a fact that it's good but you have weird/bad taste so you wouldn't like it.
Honestly, it just recognizes the fact that people have different taste. Let me give you an example.
This is an incredible song, but I don't think you'd like it.
Lol, I actually like the song, and I never usually like metal
Agreed, but there are ways some people say it where it does sound like an insult.
I see what you're saying. Tone can convey a message beyond the words.
I don't find it insulting. I take it to mean that while they like it, they know my taste well enough to know that I wouldn't.
It does sound like you have bad taste, but they may mean they're good at what they're doing, but you don't like that thing. Like Hitler was good at what he did (killing people) but people still don't like him.