I've used Moodle a couple of times, including building a course from scratch three months ago. It has a good feature set out of the box, has plenty of plug-ins for add-on functionality and - for me, the best thing - a really helpful and responsive user community. (See the forums [1])

Documentation is also refreshingly comprehensive and up to date.

[1] https://moodle.org/mod/forum/index.php?id=5