There are a lot of advantages to open source. Of course, just being open source "per se" doesn't make the solution good.
- You have the source. If the company that produced the product goes broke, you can fix it yourself.
- Peer review - bugs will be found by others reviewing your code.
- Closed source has no real reason to fix bugs because people don't know they are there. Until later ...
- Someone can look at the source and suggest improvements, or simply release an improved version.
- You can check for back doors, or other dodgy practices.
- The notion that a couple of people employed by one company can produce better code than the combined resources of experts around the world is rather arrogant.
- You don't need to worry about the company "reviewing their licensing" (ie. putting up the price) once they have you dependent on their product
In fact many commercial products use open source. For example, things like routers, networks disks, etc. You will find buried away in their documentation a reference to the GPL usually.
Take, for example, Apple. A well-known highly successful company. See this page:
http://www.apple.com/opensource/
From that:
Major components of Mac OS X, including the UNIX core, are made available under Apple’s Open Source license, allowing developers and students to view source code, learn from it and submit suggestions and modifications.
and:
Apple believes that using Open Source methodology makes Mac OS X a more robust, secure operating system, as its core components have been subjected to the crucible of peer review for decades. Any problems found with this software can be immediately identified and fixed by Apple and the Open Source community.