Disadvantages of Opensource

I'm assuming you mean open source software in general, but I'll use two readily available open source applications as an example:  Paint.Net (http://www.getpaint.net/index2.html) and Open Office (http://download.openoffice.org/2.2.0/index.html).

Both of these programs are excellent examples of well-written and documented applications from the open source community.  Paint.net even has native 64-bit support (something Adobe is still trying to catch up on).   Open Office is a good substitute for Corel's and Microsoft's office suites.

The problem from an organizational standpoint is standardization, interoperability and end-user support by the IT organization.   You really want all of your users to (within reason) have the same basic desktop application suite (word processing, email, spreadsheet, presentation, internet browser, etc.).  Otherwise, desktop support becomes a nightmare as you try to support multiple diverse applications.

From a user standpoint, you have familiarity and training issues.   Like it or not, there are many more people in the employee pool (present and future because of turnover) who have at least a basic working knowledge of Microsoft Word and Excel.   Sit one of them down in front of a machine with Open Office and see how long it takes them to become as familiar with that product as they were with Microsoft Word, for example.   Some will become frustrated, throw up their hands and ask (read: demand) that they receive training.   Can you buy a "Learning Open Office" CD at CDW?   No, you can't, though there might be a "Open Office for Dummies" book (I didn't check, but you know what I mean).  Others will dive in and do the best they can and eventually will learn to become just as efficient with Open Office as they were with Microsoft Office.

Interoperability and compatibility:  Open Office and Paint.Net have worked very hard to make sure the end result of using their products can be exported to the common mainstream applications.   The reverse, unfortunately is not always true.   For a simple "Dear Sir" business letter, it probably won't matter and you'd never know the difference.   But if you're writing a 50-page manual, or a prospectus using charts, graphs, embedded symbols, varying formats, bookmarks, footnotes, bibliography, table of contents, indices, appendicies and so forth, that's where you may run into interoperability and compatibility issues.   It's kind of a repeat of the old HTML bugaboo where you have to test your web code with different browsers to make sure they all look the same, whether it's Firefox, Internet Explorer, Opera, Netscape or whatever.

Open Source software is almost by definition always a work in progress (but then, so are most mainstream apps too).    One of the main advantages of Open Source is cost.    Compare a 100-seat license for Open Office with a 100-seat license for Microsoft Office 2003 Professional and you'll see what I mean.

Training and Support are two other issues.   Take a look through the phone book, or on Google and see how many companies offer training classes for Microsoft Office, then see if you can find ANY who offer classes in Open Office.   Same goes for IT Consulting firms, though with most consulting firms, you can usually find at least one geek who swears by open source and has three Linux machines at home and loves to poke fun at Microsoft fan-boys.

Vulnerabilities and Patching.  If a vulnerability or exploit is discovered for a Microsoft product, and Microsoft publishes a patch for it, those patches are rolled out automatically through Microsoft or Windows Update (or through SUS or MOM in a large organization).   For the open source community, you have to monitor the website, newsletters  and the blogs to find out there is a vulnerability and where to go get the associated patch for it.    This is time-critical and manpower intensive.   The good news is that because open source software has such a small market share (at least at present), the guys in the black hats turn most of their attention to Microsoft, a much bigger target and a much larger target audience.

One disadvantage that is not mentioned above is that sometimes the OpenSource project may be supported by very few people, so if they lose interest or move on to other projects, the user may be stuck without support or an upgrade.

Of course this is often true of commercial projects as well.

DrMicro47 has covered everything succinctly.

It all comes down to cost.
If cost is an overriding factor as it is, for example, in many non-profit organizations, then open source can be worthwhile despite the disadvantages for the less geeky users.
If cost is NOT a biggie - stick with the market leaders.

An example in web development.

nVu is an acceptable open source WYSIWYG web design program, but it has limits - for instance, no dynamic templates is a big disadvantage.

For someone with a 6 page personal website this is no big deal, but for a site with 50  pages and rising it's a killer blow.

A newbie web designer is well advised to move on to MS FrontPage because it does the business and is eay to learn.

However, when the newbie becomes a little more experienced and understands scripting he or she will become frustrated by FP's limitations and will be tempted to shell out the big $ for the market leader - Dreamweaver.

I'm not an expert on IT markets, but this is my take, anyway.

I've tried to make the switch to Linux several times since 1999, and have always gone back to Windows.  I recently installed Suse 10.2, and was again tempted to go back to Windows thanks to the usual 'open source' issues and one major screw up by Suse (their cpu smoking updater utility).

I switched to Ubuntu and was still disappointed by various things, but have stuck with it because I desire to develop in Linux.

Disadvantages of open source?  As was mentioned.......MONEY.  It all comes down to the bucks, one way or the other, because money represents our time.

Linux was born around 1993, so it is now about 15 years old.  15 years of work and they still don't have a fully viable desktop competitor for MS!

Ubuntu is at the top, but it still can't compete.

15 years!  How much longer do they need to figure out that desktop users have no interest in the command line? Users want to use the computer, not hack it!

To put it simply, the advantage of open source is its' potential.  But potential is all it is, and will remain so, until *volunteers* donate their precious time to turn that potential into a reality, a reality that few developers will ever see turn to cash.

The primary disadvantage of open source is...........motivation, which is the primary advantage of closed source.

Proprietary software promises a weekly check and in some cases a pot of fat gold for the hard working developers.  This gets the blood pumping with dreams of expensive homes, fancy sports cars and early retirement.

Open source promises........... that your name might be remembered for a few months, by a few fellow volunteer hackers connected to your project, and, probably the only significant plus, which is not unique to open source, that if you work on large enough projects that you can use it on your resume for a job that actually pays.  And after you secure that job that pays real money, you may no longer have time to work on the open source projects that "helped' you get the job in the first place.

Open source has fantastic potential, but right now, it's a relatively niche operation.  Give the markets and the users time to adjust, and open source will become an animal big enough to at least cripple the proprietary beast.