makes it easy to focus on what's next. Nice new web UI. Forces you to use contexts in place of sub-projects but contexts can't be shared so it adds a lot of work for organizations who need to share many projects.
Wrike is very fast, has excellent Gantt charts, tasks can belong to more than one project, has a 3-pane display, email integration, and collaborative editing of task descriptions using EtherPad
Very nice, very fast. Only one level of subtasks, no practical batch editing, no gantt chart, etc.