There are some advantages to using Open Source Software. A good description of these advantages can be found in the introduction to The Zope Book" However, put not-so-briefly in my own words, these advantages include:

• Open source software often requires no licences. Unlike some software and operating systems, rarely does open source software have a licensing cost associated with installing and running it on machines. Only in the case of using certain software packages for commercial use are you likely to find licensing costs. However, even in these instances, the costs are almost always trivial, such as a few hundred dollars for a site-wide license.
• You have the source. Because you have the source, you can make any modifications you need to make. Unless expressly forbidden by a overly restictive copyright (which is rare), you can make changes to Open Source software, and can keep them to yourself. These changes might be to fix a bug you find, or they might be to make customizations to make the software work better for you. Of course, it really is in your best interests to feed your changes back, else you will have to continue to make those changes for each and every new version of the software.
• Help is just a few keystrokes away! You can often find help from the large community of folks using and developing the software. Since everyone has the source, odds are you can find somebody else using the same software which knows what you need to know.
• You are not succeptable to the disappearance of the folks developing the software. While software companies would like for you to think otherwise they are just as prone to either going out of business or dropping support for a software package as any open source project is. However, in the case of open source software, you can continue to support the software since you have the complete source. And the odds are that you will not be alone in doing so.

However, in addition to the advantages to Open Source software, there are some disadvantages. Some of them are the result of the nature of Open Source software, while others are the result of flaws in the Open Source model. They include:

• There ain't no such thing as a free lunch! Just like with software which you buy, you must make a investment when using Open Source software. This investment is in the form of personel, but with a bit of planning, you can minimize the cost to the point where you get a good return on your investment (ROI). This personel investment may be in the form of a system administrator or manager who knows a bit more about programming. Or, it may take the form of the time of a dedicated programmer or programming staff which supports all your Open Source software along with any other programming you do.
• You cannot make a living by writing Open Source software! You must make your money either by working for a generous and unusually enlightened employer, or by charging for add-on services and extras. Otherwise, you must make your living in some other way.

  However, before you consider making money charging for add-on services and extras, such as getting releases early, etc., you have to be honest and consider whether or not you have charged a legitimate amount, or if you are scamming your customers by charging an excessive amount for a Totally Hideous Undesirable Droppings.

• There is no guarentee you will find good software! The Latin phrase caveat emptor is very much the watch phrase when selecting Open Source software. For every good Open Source project which creates excellent products, there are a hundred or more projects turning out meadow muffins!

  For some projects, the problem is that the folks writing the software have no clue about programming and software engineering. Instead, those writing the software may be students (even pre-teens) or persons of other professions who think they know how to program just because they read some book or took a class. Even a Ph.D. in Physics or Engineering with daily use of a computer does not make you a programmer! Indeed, some of the worst code which works can be turned out by these folks.

  For other projects, the saying "too many cooks spoil the broth" comes to mind. Even with dozens of experienced professional programmers, it is possible for a project to lay an egg or even a prairie patty. These are often the result of people stepping on toes, pulling a module in multiple directions, or by the use of very relaxed software engineering practices (such as forgetting about code reviews, and not compiling before submitting changes).

  Of course, with the source, you can try to fix any issues which exist!

• There is no guarentee that the software does infringe on someone elses intellectual property rights! Often, programmers might be tempted to re-use someone else's code, and occasionally they give in to the temptation. In other instances, the infringement may be unintentional due to the programmer being unaware that some corporation obtained a patent on some technique. The SCO vs IBM lawsuit regarding the possible re-use of UNIX code in Linux is an example of the first problem. Having worked with both the UNIX source code and the Linux source, I have seen several areas where code appears to have been copied, complete with typos from the former to the latter. (And no! Do not think to ask where these were located. I am prohibited from doing so by the NDA's under which I worked That is for SCO and IBM to work out inside of the protections offered by a court of law). Then there is the LZW compression patent issue with GIF images.

  And once again, with the source, you can try to fix any issues which exist!

But even with all of this considered, I still think that Open Source software is the way to go!