The quality of Open Source Software (OSS) is generally much debated. Some state that it is generally higher than closed-source counterparts, while others are more skeptical. The authors have collected the opinions of the users concerning the quality of 44 OSS products in a systematic manner, so that it is now possible to present the actual opinions of real users about the quality of OSS products. Among the results reported in the paper are: the distribution of trustworthiness of OSS based on our survey; a comparison of the trustworthiness of the surveyed products with respect to both open and closed-source competitors; the identification of the qualities that affect the perception of trustworthiness, based on rigorous statistical analysis.