Rick,
It's not such a simple answer 
.
There's a lot of backstory (changing administrations, bankruptcy) for that high school (which is why I'm no longer there) but in my last year I migrated the school to a different platform called Alma (getalma.com) which I absolutely loved as a solution for that type of school. It combined a basic LMS with a basic SIS. You could create a student database, run reports, scheduling, etc. And the price was maybe $100 a year for the student population. The visual design was also excellent-as my former boss would often say, "even I can use this!". To this day he still considers this one of my best decisions for the school lol.
Edmodo was great but it lacks any real kind of SIS functionality. We were using Edmodo with PowerSchool, but PowerSchool was way overkill for the needs of a 150 student school, hence me researching and ultimately choosing Alma. You'll see my post below about the type of classes though and these were K-12 face-to-face web facilitated and Alma fit what we needed perfectly on so many levels. Stuff Alma couldn't do we did with GAFE.
As a GAFE school, we had access to Google Classroom which I did play around with. It mimics the wall style feed of information that Edmodo does, but I found it difficult (i.e. too restrictive) in the way it handled assignments versus simply using a tool like Doctopus and Goobric. I absolutely loved those two on top of Google Drive rather than the classroom suite. But, time has gone one and I don't really know how it's changed.
I've also used Canvas as an instructor, Blackboard as a student/instructor, Schoology as an instructor, and on the rabbit hole goes . This is of where my academic background is however (MS Instructional Design & Technology and EdD Educational Technology - Online Education focus).
Edmodo needs to be used in tandem with some kind of SIS. Schoology has integration into PS but this costs $$, as does the enterprise version of Schoology.
I know Moodle can do payments and some basic SIS functions but this doesn't really work for us here in Korea for example. We simply have a separate custom built one that integrates with all of the Korean payment services, etc.
Edmodo doesn't have a robust quizzing feature (neither does Google), but, if you don't need a robust one like Moodle, Canvas, or Blackboard, then it works. Google Forms have improved tremendously over the last couple of years, but even before that with Flubaroo, they were better suited to simpler and shorter assessments.
Edmodo doesn't have forums of any kind per se, you can create groups/filters to sort of mimic a forum. Assignments are basic with due dates, file submissions, etc., but you can't create a web page/prompt that might be related to that assignment. You'd just have to link to those resources. File management within Edmodo traditionally was a bit difficult, though they have integrated with Google Drive some time ago, and now a number of other services.
If you look into the definition of the spectrum of class types with "technology" from Allen and Seaman (2014), you'' get:
0% Traditional Course where no online technology used — content is delivered in writing or orally.
1 to 29% Web Facilitated Course that uses web-based technology to facilitate what is essentially a face-to-face course. May use a course management system (CMS) or web pages to post the syllabus and assignments.
30 to 79% Blended/Hybrid Course that blends online and face-to-face delivery. A substantial proportion of the content is delivered online, typically uses online discussions, and typically has a reduced number of face-to-face meetings.
80+% Online A course where most or all of the content is delivered online. Typically have no face-to-face meetings
Further reading if you like: http://www.onlinelearningsurvey.com/reports/gradechange.pdf
You'll find that all of the CMS/LMS's (and even BMS-Behavior Management aka Class Dojo) will fall into some part of that spectrum well, and then of course somewhere in between. I think Moodle is perfect for the upper part of Blended/Hybrid and Fully Online (per this definition) whereas Edmodo is much better suited to the lower end of Blended/Hybrid and Web Facilitated. These are very loose approximations, though .
