I had tried Edmodo, but for several reasons, I switched to schoology this year. First introduced to me by Hebrew School students I taught who attend Ramapo Indian Hills School District, I like its easy user interface and similarity in operation to facebook. Does it undoubtedly have flaws? Yes, the IM to cell phone feature and lack of integration with powerschool without paying for it is not ideal. However, the ability to fully flip a class when desired, the opportunity to interact with students on inline discussions monitored by the teacher and only visible to the class, parents, and teacher, the online testing feature, the polling feature, syncing to dropbox assignments, and the fantastic amount of data that can be uploaded onto each class site (powerpoints, videos, etc), make it unparalleled to anything else out there.
I use it for both courses and clubs. I have already worked with many educators helping them set up accounts for themselves and their students. There is a solid reason why many large elite public school districts use this site. I'd encourage all to check it out. Feel free to contact me with any questions you may have.