I have used FictFact, Shelfari, GoodReads off and on for a while now. I always seem to fall back on FictFact for one very specific reason: It has a very simple way to set all books in a whole series as read without clicking each and every book in the series! Two clicks and I am done!
What gets me for sites like GoodReads or Shelfari is I have to manually click each book and then go through a popup to get that book in one of my lists. Some series are pretty long that I find it tiring doing that for each of my books when I read them in bursts.
The only downsides with FictFact is it only lists series not standalones.
The only good thing Shelfari has going is the ability to import your amazon book orders into your shelf.
Maybe in the future FictFact could pull info from a import amazon book orders list.
Sites I talk about:
Music of the post: