Well, sure, but the person reccing to you is still heavily influenced by what *they* like, right? I mean, there are certain people in RL whose recommendations I don't trust any farther than I can throw them. My mom is one of those -- what she likes/thinks I'll like, and what I actually enjoy, are worlds apart. (And makes gift-giving problematic as well ... my idea of an OMG AWESOME! book or DVD is just as likely to bore, confuse or offend her, even when I'm trying my damnedest to get inside her head and figure out what she might want.)

but I would like to know if someone is reccing something because they think it's a high-quality work of fiction, or because they can't get enough of X and so even badfic is good to them if it contains X.

Yeah, that makes sense. Although you know, even there ... it's damned hard sometimes to figure out if something I think is the most awesome story since forever is actually just hitting a particular kink I didn't know I had. Most of the time, I think I'm capable of distancing myself enough to recognize that a given story is really not that well-written objectively, but is a very effective example of [x] fanfic trope that scratches a particular itch of mine -- but I'm not that self-aware all of the time, and I imagine a lot of reccers aren't either.