My original reporting of the Goodreads/LibraryThing stats for the Best Novel shortlist omitted the eventual winner, which was added only at a later stage. I've rerun the numbers, and the order is about the same, with The Three-Body Problem in the same rank as Marko Kloos' Lines of Departure:
|owners||av rating||owners||av rating|
|Skin Game, by Jim Butcher||34,039||4.55||844||4.31|
|Ancillary Sword, by Ann Leckie||8,858||4.05||551||4.09|
|The Goblin Emperor, by Katherine Addison||6,220||4.08||508||4.23|
|The Three-Body Problem, by Cixin Liu||5,980||4.00||394||3.82|
|The Dark Between The Stars, by Kevin J. Anderson||664||3.54||75||3.11|
Not very surprisingly, this reveals that The Dark Between The Stars was a very weak choice, with by a long way the lowest rankings both of ownership and of user rating on both systems. Skin Game clearly has a lot of fans who rate it highly, but I don't think it would have won even if it had reached the ballot without puppies; Hugo voters have very rarely backed a later book in a series where they have not already given the award to an earlier one.
A little more surprising is that The Three-Body Problem is second last on both metrics on both systems. On Goodreads it's within the margin of error, but on LT it is quite some way behind in ratings despite a similar level of ownership. This of course demonstrates only that Hugo voters have different opinions from users of Goodreads and LibraryThing, and that consequently statistics from the latter are of limited value when trying to predict the behaviour of the former.