The simple answer is: quality, value, and stability.
This question has been asked and answered many times over. Therefore below, we are only going to give you our-take on what OSS means for business. Please feel free to search the internet for more comprehensive and detailed reasons.Quality
Quality, feature-for-feature, open source software meets or exceeds quality standards set by industry leaders. Quality features that directly compete for your business; designed and developed by thousands of developers completely devoted to producing quality solutions. Quality, for which is not only a goal but a mission / passion.
Leaders in the commercial non-open-source industry also produce quality products, but often only driven by profit which have negative impacts on quality, features, and price. Commercial, non-open-source, product quality levels really depend on money and resources devoted to the product. Money and resources, when not available often result in partial products, missing features, and poor usability. We are not saying the quality issue applies to all commercial non-open-source products, but rather the approach to quality is different and driven by different motives, which ultimately impact quality.
Open source software is not without it's share of quality issues either. However, when quality issues do occur, you are completely free to fix it and contribute your fix back to the community. Everyone using open source software may contribute to improve quality, which you simply don't have in commercial non-open-source products.Value
Regardless of what you see or read open source software is not free. The production of quality software takes time, resources, and money. The free aspect of open source software is about freedom not price. Freedom to do what you want with the software; own, share, sell, or modify to name a few freedoms. Many, but not all, open source software projects provide products for free.
Value in open source software comes from freedom not price. Regardless if the product itself is free or not, most allow you to do what you want with the software. As an example consider server software; with the Microsoft server product you cannot simply copy the software onto as many computers as you want. You must pay for every single copy. However, with Ubuntu server you can make as many copies as you want at no additional cost. The same is true with common office software. The Microsoft office product requires you to buy a office license for every single user in your organization. However, the open source product, LibreOffice, or OpenOffice do not have this restriction. Additionally, the majority of open source software does not require expensive upgrades providing even more value.
The value in any software product boils down to it's license model which dictates what you may or may not do with the software. Commercial non-open-source vendors have varying licenses as does the open source software vendors. The "many, but not all" terminology we used above has overall impact on value to your business. You will need to learn about the different license models of open source software to determine if you ultimately receive value from the vendor's product. To learn more about licensing this link to the Open Source Initiative is a good place to start. OSS Licenses By Category Also, here is another useful link: Open-Source Software LicensesStability
Our experience with both commercial and open source software, has taught us that stability, at times; is a relative term. However, we find through usage and testing; open source software has been extremely rock-solid-stable and predictable with far fewer bugs. Software with thousands of volunteers (and paid authors / developers) do a fantastic job of catching quality and stability issues. The net effect is a more stable product.
We will point out not all open source software is stable and it's the business owner's responsibility to carefully check (and test) which versions are stable or not. Most quality open source projects clearly indicate what versions (alpha, beta, stable, unstable etc..) are available for download, making it easier to decide what is right for your business.