schneefink asked: favorite kinds of AUs?
Reading other writers' AUs:
When someone else has created it, I like a wide range - really, anything goes. Close-to-canon fork in the road deviations, AUs which are canon-like but with significantly changed tropes or elements, and wildly different AUs where the familiar characters are in a totally different setting.
With close-to-canon ones I like it where the writer can imagine how differently things would fall out if one salient thing changed, and then write that convincingly. Martha Wells' Retrograde verse is a good example. Canon-warped AUs can be fun - like there's still the Stargate program and they're on Atlantis, but Rodney turns out always to have been an alien - Eliade's An Aesthetic Solitary Thing, or Hawaii five-O where Danny's a mer-person and transforms into a shark (Between the Devil and the Deep Blue Sea by JoeLawson). Then there are the totally different AUs which for sci-fi fandoms are non-sci-fi and set on Earth. Depends on the fandom - in SGA they tend to be historical, or romantic comedies or dramas. Examples are rhymer23's The Pirate's Prisoner (C18th pirates, SGA), Hawks and Hands by dira sudis (Hockey AU, due South), or Patience, a Steady Hand by helenish (Viking/Monk medieval AU, Inception). In non-sci-fi fandoms of course, they can be space-based, like toft's Robots Need Love Too (Mythbusters RPF space AU).
The only AUs I'm not massively fond of are very trope-heavy Harlequin-type romantic AUs, and even those are fine if the writing's good.
Writing AUs myself:
I tend towards extreme AUs but some are canon with significant changes like A Boy Named Jay which has John and Rodney as cis-female, but otherwise still on Atlantis in their respective roles.
Most of my AUs are more complete and many are fusions with another verse, like In the Drift - SGA/SG1 in a Pacific Rim fusion verse, or Evening the Odds, which is The Losers in a space-pirate Firefly-like verse.
I'm not good at the canon-divergence ones, mostly as I'm generally too lazy to do all that canon research and as I prefer the wilder flights of fancy to a story that just veers off a bit and then ends up someplace different. Plus I love fusions and crossovers as then you get two sets of fandom references to play with! I haven't done the stats but I suspect more of my stories are AUs of some sort, than non-AUs.