Please note. When trying to employ a good roofer, take into consideration the number of reviews, positive reviews and number of negative reviews. A roofer who has a five-star rating and under 20 reviews, will possibly not be as reliable as a roofer who may have 50 positive reviews and no negative reviews. Google’s algorithm is based on a combination of factors, including the quantity, quality, recency, and velocity (frequency) of reviews, relative to local competitors.