What are the best WBS and Gantt chart tool working cross platform? I am searching for the good tools for creating Work Breakdown Structure and Gantt Chart that work cross platform because other people in my team use Window. So, this forces me to find cross platform tools.

What have found so far are : 

OpenProj : I have used it. The behavior is so quirky that why I gave up.

GanttProject : Cool tool! It can be used to create Gantt along with PERT chart. However, it cannot generate WBS chart.

I have searched a lot and I didn't find the one that I love. 

Could you please share your great tools that you are using along with advantages and disadvantages?
http://teamgantt.com … used by Oracle, Twitter, Sony. You will have to call whether their features are close enough to a WBS to be acceptable.
Allows for CSV file import (a file format exported by MS Project).