In my experience WordPress offers more community support and security. Much easier to find help and solutions to accomplish what you want. Joomla requires more technical expertise and has less support.
I had a Joomla site once. It got hacked and I never got it back. That was a lot of money that just disappeared overnight.
I've used both, but I find it easier to work with Word Press. Not only is Word Press more user friendly, but the information and technical support available far surpasses that of Joomla.
That brings up a good point about back-ups, make it a habit! With Joomla, manual back-up and restores were the only way. With WordPress you can just click on "export" or "import". There are plugins to email you backups automatically. (Weekly or monthly is adequate for most sites.) But the best defense is blocking hackers in the first place. I highly recommend WordFence plugin for security. It uses a community wide bad IP list for starters. Also checks your files for any changes daily. Emails you if anyone logs in as Admin. Blocks hackers and sends you a notice. WordPress is Just2EZ, that's why I use it! (that and it's FREE, no strings attached) Free and Easy, what more can you ask.
Wordpress wordpress & wordpress. Easy to build, more functionality with various plugins and very SEO friendly.