I'm using it since about 3 years now, but never really felt that there was anything i could not do via its very good helpdesk service or by phone support (which is free!). It's also easy to integrate into our project management software which we use in combination of Asana for task assignment/communication etc., so all team members are able to track their progress at any time from anywhere! There isn't much, as you can get what u need through out-of box stuff plus great community around here ;)