While I am not opposed to closed source or proprietary software, as others may be, I very much appreciate software that is open source. I view it as a feature: a very attractive feature that can be implemented in any piece of software.
When I install a piece of open source software, I can be reasonably sure that it does not contain any adware, spyware, or trojans. This is simply due to the fact that such things are not tolerated, and if the program is at all useful, someone will have noticed and called the software developer out. Once this happens, if the original developer doesn’t modify the software to remove the malware, someone else will undoubtedly create another version - this time without the offending bits; this version will then become the de facto standard. This is my single favorite benefit of the feature of being open source, especially when it comes to other people’s computers and the repairing thereof.
No Dangling Bits
I also can be reasonably sure that a piece of open source software is easily and completely uninstalled from a system. Many shareware and freeware apps are simply of very low quality; either the installer or the uninstaller or both may not work correctly. This is another example of bad software behavior. Over time, installing and uninstalling shareware and freeware software contributes to a very messy system with orphaned libraries, pointers and other files. This is another software behavior which is simply not accepted in open source software.
A Great Tool
There are many other more technical reasons open source software is great, but they don’t apply directly to most users. However, I would like to point out one somewhat technical benefit: open source software is a marvelous tool for learning to program. There is a stage that comes after a person learns a first programming language but has not done much programming. At this stage, being able to see and modify the source code of programs is very beneficial and empowering. This can also help someone get involved with a community of software developers.
Open Source is more than an ideology for me: it’s one of the best features a piece of software can have.