First off, it's important to keep in mind that Adobe Business Catalyst provides a number of automatic features which you will have to do yourself or pay to have done with Wordpress. For instance, in Wordpress you'll have to regularly backup your site, update Wordpress and the corresponding plugins. Additionally, it's in your interest to "harden" a Wordpress site for security and you'll probably want to use a service like Sucuri (these people are awesome!) on an annual basis to ensure it stays clean - even a slightly outdated plugin with the smallest vulnerability can become a vector for malware - we've seen this happen multiple times with less secure shared hosting and with dedicated servers, and it ain't pretty.
Earlier today we received a support request from someone who is moving away from Adobe Business Catalyst in favour of Wordpress, primarily because they don't believe they use the features that ABC provides. I get asked a lot about the Wordpress/ABC comparison, and thought this would be good to share, since most people believe all they need is a backup of their Wordpress site for it to be 'okay' but in our experience that's not the case.
Just a couple of months ago, we had to oversee an extensive malware removal process in a website due to a plugin that was "silently updated" - meaning the company who owned the plugin updated it against a major security risk, but didn't notify users directly and furthermore, no update was indicated as available in the client's Wordpress CMS. What this meant was that more than 100,000 Wordpress websites were compromised in short order, no one being the wiser until it was done.
And yesterday - literally, we had confirmation that an old Wordpress website that we were retaining on our own server for a client has been compromised and we discovered this though noting excessive CPU resource allocation - essentially, the compromised site was causing our server to reach maximum load, crippling our online office (ActiveCollab) and Support (Kayako). We assigned backup and removal of the compromised Wordpress site yesterday, so hopefully that will be actioned today and we can clean the rubbish off our server. (I warned you this wasn't pretty).
Overall, there are a wide variety of benefits that come from using Adobe Business Catalyst, such as automatic upgrades (generally these don't impact the front end), continuously upgraded security and general backup data - many of which are 'back end' meaning you don't have much to worry about or do, on an ongoing basis - very little maintenance is required, and very little can or does go wrong, from my experience. My server coordinator says, "I personally sleep better at night knowing this, but then again, I'm the person responsible for coordinating fixing Wordpress websites ;-)"
So after reading this, should you still want to move to Wordpress, we strongly suggest that you consider a hosting service like WP Engine, however it's important to note that the minimum monthly fee ($29) is similar to ABC, but at least you'll be able to have a high degree of confidence that your website is in good hands!