For a very basic simple neat looking calendar it's great. But put a challenge at it and it's limited. ACL is a killer, We are on Joomla! 3.x now and decent ACL support was introduced in Joomla! 2.5?
Thanks for you feedback. We are aware that ACL is something that some of our users sometimes miss and we see how it can improve Ohanah. We are already working on it, so that soon we will be able to bring you the best experience and great control over Ohanah.