Here are some of the reasons why I would continue to recommend Moodle over other LMS platforms:
Open Source: this is a big deal for my district and for me. We believe in the principles behind the Open Source Movement that leads to innovative developments. This is also important as it allows us the ability to make subtle changes to the core software to better suit our needs. We don't do a lot of hacking to our sites, but we do enough that it would likely not be possible to expect those services from a vendor solution.
We can self-host: Another big deal in my district. Because of the integration with other tools it makes sense to have full control over our LMS so that we do not have to submit requests for help. Having FTP access to our site also allows for countless hours to be saved when importing content, IMS packages, large courses, etc. There is the added pressure that if something breaks then we don't have anyone to yell at, but I'm confident in our teams ability to problem solve (this is another added benefit of the open source movement. There are hundreds of people in the Moodle community who are willing to help).
Adoption of Moodle in other districts: Moodle appears to be the overwhelming platform of choice for K-12 districts across Minnesota. This allows for some unprecedented levels of collaboration and content sharing. In my district where we try to serve the needs of our member districts it is imperative that we provide expertise in the systems in which they and our students are familiar.
Customization of course layout and design: This is probably the biggest reason we will be sticking with Moodle. We can make it look however we want. We stress the importance of course design to increase student engagement and easy navigation. No one wants to log into a course and be greeted by a wall of text or links. It's ugly, intimidating and stresses out learners. Just because an interface may look a little more like Facebook doesn't mean it can be adapted for multiple uses...
Flexibility: The ability to customize to serve a particular purpose. This is a must for teacher preference and differing outcomes between programs; staff development; resource sharing. We use Moodle for many different type of groups and learners.
Add-ons: In the event you need Moodle to do more than it does out-of-the-box, there are multiple add-ons that provide the desired functionality. I'm a big fan of Checklist, BigBlueButton, Lightbox and more. They're easy to install and update, just like Themes and the Moodle software itself.
I've tried not to reference Schoology specifically in the argument for why we use Moodle, and it's not that it cannot do some of those things I mention above. It just does not do all of them, nor does it do some of them as well as Moodle. Schoology has a great social networking feel, but in many cases it will require too much work for teachers to continually make updates that could already be finished and ready to go in Moodle. If you have students who may only log in once or twice a week; or students who may be coming in at anytime throughout the year then the social networking layout is quickly one of your biggest navigation concerns.
It would be difficult to create the kind of context we currently strive for in a platform that was made to look and feel like a social network. This could be an interesting approach to aces with a group of highly motivated and engaged learners if that is the population you serve.
The ideal is to move toward a more individualized and asynchronous approach to education, that is not the role that social networks provide. They can be an important element of learning, but the skill building resources must be offered in other ways for those programs with rolling enrollment and people who are looking for "just in time" resources/learning.
It should also be noted that if a teacher wanted to, they could set up their Moodle course to operate more like a social network, but I think they'd quickly find that this isn't what they are looking for. It could be one part of the total solution.
With the new features added in Moodle 2.2+ like course completion; conditional activities; mobile recognition and rubric grading, it is probably still the front-runner in terms of what can be accomplished with students.
The bottom line is that many Moodle users/teachers aren't trained and supported sufficiently so people tend to think that Moodle is ugly or doesn't work. That's not the problem of the software. You'd likely think the same way about any software without someone coming along and telling you what is possible. At my district, we've made significant progress in this area and have shared it with the rest of the world. We provide even more resources to our own staff and member districts. Very soon we are likely to have a large number of incredibly talented course creators that will produce content that exceeds what can be accomplished by using vendor materials.
Too many districts are going to fall for the initial look and feel of other platforms and quickly regret the decision when they are ultimately locked out of the incredible community of content creators and multi-district initiatives that are currently being started in Minnesota.