Wordpress and Joomla are both just tools at the end of the day and can both be effective depending on how you are using them. I personally have had negative experiences trying to optimise existing joomla sites (complicated templates, weird plugin functionality, slow load times etc) but I am sure those more experienced with it would say these things can be overcome.
The real questions are why you want to switch systems and how much effort it would require to do so? It looks like you have quite a bit of content in your site, so migrating to wordpress would likely need a bit of technical experience and time to complete. I am sure there are scripts around that will help in that process, but migrating a db from one system to another usually has a few gotcha moments along the way! You would also need to account for any changes in url structures and 301ing the old urls to the new. All in all not a decision to be taken lightly.
If there is not a specific reason you want to switch (ie something you are trying to do in joomla that is proving impossible for some reason) I would think that switching platforms might be more hassle than it is worth. As for one or the other being more customisable and/or secure than the other, I don't think there is really any difference between them, both are fully customisable and are as secure (or not secure) as you make them if following best practices.
, but man, those links are pretty powerful and even though the event could be considered a negative one from one side of the equation those links are probably giving a good overall authority boost to the site.