We have created Client Users so that our clients can see the progress of their project live, but we are concerned that clients can view the Work Hours of tasks.  For us the work hours is commercially sensitive information which is used to develop the cost of the project to identify the 'selling' price to the client.  We need to put the Work Hours against tasks, to track planned versus actual time/cost, but by no-way should a client be able to see this.  
By letting the client see the Work Hours, they could effectively be able to back calculate the charge our rates or profit budgeted against a project.

Please make the Work Hours field not visible to Clients.  If possible provide an option to show the field if the task is assigned to them only.