The thing that really clinched the deal was the fact that there are few really good iPhone and iPad blogging apps available, allowing the user to edit and create articles right from their portable tablet or phone. This alone is worth gold and a major reason for me to come back and experiment with WP again.
I still came across the same stumbling blocks as before, like the menu systems not being particularly great or easy to manage, however after using your local friendly search engine, there are some Plugins available to help achieve a better system.
I'm using a great app on my iPad as I type this, it's called BlogPad Pro. It's far better than the standard WordPress app too, it comes with a wysiwyg editor for posting, lets you access menus, media… On it goes, well worth £2.99!!
As for Joomla, I have seen some apps appearing in the App Store, however they are still in their infancy and need further development to compete with the WordPress examples. The Joomla equivalents are ok to use with the generic article system but do not currently support article management components such as K2. Generally a majority of Joomla admin's are moving over to K2 style content extensions to give them greater flexibility and control over their content. I must say having used K2 in a number of web sites I've developed recently, it's very powerful and extremely customisable. Unfortunately, as I say – there are currently no apps [at the time of writing] that support the likes of K2.
Anyway, I like being able to 'blog' on the go, it passes the time on the train each day, gets me writing and let's me dump stuff to unclutter my mind!