I still think context is everything in responding to other's ratings on GR.
For example I find that at lot of frankly pretty rubbish but frequently 'exciting,' mass produced (as in the 'author' produces in excess of 20 or 30 books a year), trashy pulp fiction get rave reviews averaging well above 4.0. Whereas more 'serious' books like, for example, 1984, Brave New World etc., that frequently are somewhat less accessible and demand a lot more from the reader, get much lower reviews. So I can't simply go on the rating alone, being someone who frequently likes those more 'serious' books.
So for example if I'm looking at space opera or military SF, both sub genres that I thoroughly enjoy but that also suffer some of the worst levels of trashy pulp and overinflated ratings, then I will rely heavily on authors known to me, personal recommendation or GR reviewers whose opinions I already respect and what their ratings are. When I'm looking at more 'serious' reading especially translated stuff including, but not limited to, magical realism, from authors like Murakami, Marquez, Bolano, etc., then I'm much more concerned with the author and the ratings given by known GR reviewers.
It's difficult and the ratings are, as ever, only one part of the equation. As with buying online, I often pay more attention to what the reviewers didn't like than what they did.