I tend to ignore good reviews and rely on bad ones mostly to make my decisions. Will also never leave a good review when I'm satisfied, they are indistinguishable from fake ones anyway, I tend to rather just leave bad reviews when I'm not satisfied.
The problem is that bad reviews can be just as fake as good ones, as they could be written by the product's competitors. Also, if a product is popular enough, odds are that even with a great product there'll be a small fraction of people who'll just happen to get a dud, while most of the rest will be satisfied. Because of this, I tend to read both good and bad reviews, and give more weight to the longer reviews that…
For me, it's the 4-star and 3-star reviews, and distribution of them compared to the rest (this can be gamed though). I see no reason that somebody would pay for 4 or 3 star reviews, and also competition would pay for 1 or 2 star ones instead. Primitive logic, but worked +-OK for me even on Amazon.