I did not know what OSS was and don’t really know if I have ever had any experience with it. I don’t think I have.
All that aside I did some research on it and have some idea as to what the advantages and disadvantages are.
Advantages-
New features are included regularly and in a timely manner
If there is a security breach it is usually fixed pretty quickly.
So many users and programmers are involved that there is a wide pool of people to whom you can ask questions and gain input regarding possible improvements.
Disadvantages-
Sites/programmes can be difficult and expensive to maintain if you don’t like writing code of don’t know much about writing code.
If you are in a hurry to get bugs fixed you may have to resort to paying someone to have them fixed quickly.
The open source community is not obliged to answer all of your questions, so they often go unanswered.