For movies a histogram may not be helpful (other than highlighting polarizing films), but I find it invaluable for electronics. While I also read reviews, I find that with electronics 1 star reviews (and sometimes 2 star) are usually given for DOA or other serious failure. I can do a quick calculation of defect rate by calculating the percentage of 1 star reviews. If it's 20% (or above norms for that product type) I avoid it. And yes, I realize that the reported defect rate is likely to be higher than the actual defect rate, but it's far better than nothing.