There has been much debate over the popular Content Management System's (CMS) such as WordPress versus other closed proprietary systems. I am here to dispel any false accusations or overblown problems dealing with Open Source software, and more specifically WordPress. I will be taking points from a blog post I just recently came across talking about the pros and cons of WordPress. http://www.webnology.co.il/knowledge-base/open-source/pros-and-cons-of-wordpress. Although I reference WordPress as an example, most of the below points apply to open source CMS's in general.
Problem 1 - Its open source structure
since all of your system’s code is available online, it is also easy for hackers to find security holes. Moreover, every programmer having engaged in prior usage of this code can intentionally plant malicious code into the published code. For example, you may have a plugin installed that allows you to easily send out newsletters. What can happen, however, with the circumvention of your knowledge, is that it will transfer your entire mailing list to the plugin developer.
Although it is true that the source code is readily available to the public, this doesn't indicate that you are destined to be hacked. Similar to a proprietary system, you put trust in theme and plugin developers to not use these "tactics". The one difference with a closed source platform is that you have to "blindly" trust that they are not inserting malicious code without your knowledge. If someone develops a plugin for WordPress, they are putting their code in plain view to see for the whole WordPress community. And considering the large number of developers who are on the platform, they are bound to be found out fairly quick.
This is a point where you use common sense to vet plugins based on reviews and other feedback. Remember, the larger the plugin is in the community, the more it will be scrutinized by its users, and naturally the safer it becomes.
Which bring me to point number 2
Problem 2 - Updates
updating the system is critical to close security holes that may pop up. However, since each WordPress site includes countless different plugins, updating the system can damage certain plugins not adapted to the new system. Basically, the site will then be at the mercy of the programmer who wrote the plugin – and will show in a suboptimal way until repaired
There doesn't exist software that is completely secure, closed system or open system (Even the almighty Apple Major Apple Security Flaw). As a result, there will need to be an ongoing check for security holes no matter the system. With that in mind, let's say a WordPress update comes around, and a plugin, or addon breaks due to incompatibility. The greatest advantage here is that there is an enormous community who has experienced the same thing.
And guess what happens? Developers that aren't even a part of the developer team who made the plugin can "patch" the plugin until the official developer has time to come around and fix it. Alternatively, if you are on a closed source, proprietary system, you have no choice but to rely on one company to fix the problem.
If I had to choose between being held hostage to one company (whose main goal is only gaining new customers), or have a community being able to continually improve a system, I choose a community every time.
Problem 3 - Control
WordPress releases system updates that are good for WordPress and not for you. If your needs are the same as those that WordPress try to address, you are lucky. Otherwise you might get updates that harm rather than improve the website
There is no way to comment on this in detail. By definition, a closed system doesn't allow any control but by the company who made it. This is good for the company, bad for the consumer.
Problem 4 - You’re no different
WordPress sites tend to look similar to each other, even after theme and color adjustments. The question is whether a company that invests a large amount of time and effort in PR, wants its website to look like many others’ (as many large companies cannot afford that its customers will associate its design with another brand)
This cannot be further from the truth. There are hundreds of thousands of themes developed for WordPress a year. Even non-developers can plug in to massive theme customization without knowing a single piece of code.
In conclusion, there isn't a right or wrong when choosing how to build your website as much as it is a personal preference. But for me, I would prefer being able to own my own website and modify as I please.