I have recently done quite an extensive search for Project Management software for a client. I believe HyperOffice will be the clients choice because it has a full email client. I however, for my VA business, use a difference PM program.
I use Intervals
http://www.myintervals.com/. This is a reasonable priced SaaS solution with GREAT reporting capabilities. You can report time and subtotal based on project or task. (Subtotaling by task is a rare feature to find.) It also has an invoicing feature which is quite nice. Additionally it allows my clients to access a large variety of information and email tasks directly to the project management system. The software is priced per project, not per user. Therefore I setup a project for each client and use tasks and milestones to track workflow.
Another good PM program is WORKetc
http://www.worketc.com/. I previously used this system. It has some great features. I switched to Intervals from WORKetc due to the wider rage of access my clients have on Intervals. (WORKetc does not allow a client user to see or respond to tasks. A deal killer for me.)
For me the biggest disadvantage to most of the other Project Management programs out there is the time tracking and time reporting interface. Most other programs only allow one enter per tasks per day. Therefore if you work on the same task several times in a single day for a particular client, then you have to manually add to the tasks time each time you make and entry.
For example: Scheduling task. I have a task called scheduling for a client. I may log time scheduling 4 to 5 times a day for this client and I input my time each time I preform this task. With other programs I would need to go to the "timesheet" and manually change the number of hours logged for this task each time I preform the task. With Intervals or WORKetc, I launch the time input pop-up, enter my time, choose a project and task and submit. (WORKetc also has a nice desktop timer.) The time is now logged and will show up individually if needed in a report. (Nice for those clients who want to see the details of how you spent your time.)
Another feature I like with Intervals is that I can log time as a decimal (0.25 hours) or as minutes (0:15). The program recognizes either type of input. If you enter it as hours and minutes, it will automatically convert it to decimal numbers.
Just my two cents.
Good luck in your PM search, they are a great resource for a VA. I know my PM program is an important part of my daily business.
Julie