I am often asked why I have switched from using Rainbow Portal to DotNetNuke. I promised I would answer that.
Both products have matured and maintain some distinctions. Rainbow (RB) is written in C# and DotNetNuke (DNN) is in VB.NET. That no longer matters to me because I am not working on the core of either product. Also, I recommend that unless you can get your code added to the core product or you are planning to support your own branch then you should avoid touching the product source code as well. If you change a copy of the product you set yourself up for challenges with future upgrades. Extensibility projects or modules can be written in the .NET language of your choice so I do not consider the language argument to be valid anymore.
The other major distinction that might be worth mentioning is localization. From the beginning RB has supported localization and it is the only 1 of the 2 products that currently allows for easy content localization. Both products now support localization of menus and commands fairly well. DNN is aware of their deficiency here and they plan to address it as some point.
Usability is the biggest reason I now use DNN. When I first tried version 3 I was amazed at how quickly I could add a page (tab) and fill it with modules. I was further impressed by the content editor’s experience. In many places where you are creating a link you get a common control that easily lets you choose between linking to a page in your site, a file on you site or a URI offsite,. The file dialog really won me over. It is very common for users to want to upload a PDF or Word document and then create a link to it. In DNN you never have to leave the link edit page to accomplish all of that. With RB it takes several clicks and some intermediate end user training to handle the simple document upload and link creation process. It is so painful in RB that my team typically does it for the content managers.
The other major reason for my switch was the community. I was fine with RB because I know the people who created and maintain it. However, those I work with and who manage the many websites at Idaho Commerce and Labor have no relationship with RB’s creators. If I were to take a new job or simply wanted to find some training resources for them it begins to get ugly fast. The DNN community is so large now that you can find just about any help you need without calling up one of the core team.
Largely due to the size of the DNN community I also found a rich and active market for extensibility of the product. Mostly I am referring to the huge number of 3rd party modules that are available at very low prices. Often I have requests for new features on our websites and with RB I always had to replay with a number of hours it would take to custom build that functionality. With DNN I now replay typically with a list of 3rd party modules and their purchase price. The prices are very palatable to almost any DNN user and often you can find working solutions for free.
I should also mention that I have found DNN skinning to be reasonably easy and far more desirable than classic RB skinning. I know that RB now has the ZEN skinning engine, but I am very happy with the DNN solution and skinning must remain reasonable simple for any solution to work well. I know that RB ZEN took some magic in the page lifecycle to make it work. DNN is much simpler in its implementation with standard .NET user controls as Skin Objects.
A brief note also needs to be included here about the roadmap in DNN. Namely, they have one and they try to stick to it.
Personally I can see no reason to go back to RB and every reason to believe that DNN will be a great solution for some time. It already is an amazing content management tool and application development platform. I view DNN less as an option and more as the default foundation for nearly all sites and applications. The best way to decide between RB and DNN is to spend a few minutes with each. I think you will be surprised to find how much better DNN really is.