I was a DNN Software (formerly DotNetNuke) fan from past 15 years. When I created my personal Website in 2005, I used DNN Software. We could host multiple Websites on a single DNN instance was a really great idea. For hosting multiple Websites, I created domain alias which resulted in cheap hosting for couple of years. Out-of-the-box modules were more than enough to create a personal Website.
Reasons for abandoning DNN
Difficulty developing complex modules
Gradually, my Websites became complex. Apart from information, the Website became the Web Application where it would take input data, process it and show the output to the user. Initially, I created those applications as custom modules or using subdomain with stand alone applications. Maintenance became a nightmare. Also developing modules was a headache as custom module required digging deep into the source code. Many times I found inadequate comments and documentation within the source code wasting my time and completely abandoning the development.
This was a turning point for searching for alternative. Even though I was using WordPress as a blogging engine along with DNN, I never thought about using only WordPress for the Website and Web Application. Plenty of detailed documentation and ease of digging into the source code helped me decide the platform I would use for my Websites.
Lack of optimization
DNN was developed using Web Forms. Rigidness of Web Forms made it difficult to optimize the Website. Each module had its own CSS and HTML layout. In order to create the layout we want, we needed to create a hack.
DNN Database size generally grows larger. Generally shared hosting environment is already slow which adds up. Even though I managed to get good enough performance, I was not satisfied.
Reasons for choosing WordPress
Ease of customization
We can create complex modules while keeping the overall look and feel as it is. It gives full power of php and still works as CMS. We don’t feel burden of WordPress when we develop the modules.
Plenty of web hosting choices
We are not restricted to only Windows hosting but now we can choose Linux hosting if we choose to.