AdvantageLumber.com appears to be a legitimate company based on customer reviews. The site has an average rating of 3.7 out of 5 on Trustpilot, with 82% of reviews being 5-star. Customers have praised the quality of the wood and customer service. However, there are also some negative reviews mentioning issues with damaged shipments, poor communication, and lack of refunds. Overall, the company seems to have a mix of positive and negative feedback, indicating it is a real business but with some areas for improvement.