I'm fine with various forms of fan content, but I tend to avoid fan-fiction because it's mostly horrible. That said I have indeed read a few fics, and they were good, but I still don't actively seek it out. Part of it is like I said, there's a lot of bad, but I'm also somewhat restrictive on what kind of fan related things I even bother with. For one, I don't like AU or anything that changes one of the fundamental parts of the fiction it's based off of for the most part. Whether it be changing the canon history or introducing a character that would never happen, or anything like that. If I'm gonna look at something I'd rather it have discussion value of the show it's based off of. Basically I prefer to read things that cover aspects of the fiction that the original material hasn't gone into yet. For instance in My Little Pony, I might be willing to read something about some of the events that occurred during Celestia's 1000 year solo rule. Or maybe I might read something about a character with no relation to the main characters, but otherwise still happens in the same universe. So maybe something like a Doctor Who fic that is told from the perspective of some random guy during the year of hell or something like that.
Basically I never want to read anything that messes with established canon in any way, and is unlikely to become obsolete with canon that might be established in the future, so stories that take place in the future are also unlikely to appease my taste. Of course naturally because I don't want to read anything that messes with established canon, and I'd rather be able to talk about the plausability of anything that doesn't, I usually end up just discussing the basic fan-theory itself on forums rather than read a story that I can have to input on as I read it.
Now, my exception tends to be when the fanfiction is extended beyond words to something like a comic or even as far as a video like an animation. Doing something like that means that the writer is forced to re-read their work a lot, and as such it tends to be much more refined due to the extra work being put into everything. For example I'm quite fond of the comic series the reimagines mlp as a magical-girl style manga where the population of equestria was shunted to Earth and turned into humans a last-ditch effort to save everyone, and nobody but Celestia remembers the true history of the world; and naturally the villains were transported as well. I also like discussing BrightHammer (an Alternate take on the Warhammer 40k universe with one minor change in it's history) As it is an interesting thought experiment akin to Warhammer itself and has a lot of discussion value. Then on the other hand I have no interest in reading the likes of Fallot: Equestria or things of that sort.