I use HP Quality Centre (QC) for manual testing and test management, soon to add Quick Test Pro for Automated regression testing.
I am using Ontime as primarily a Defect and Feature tracking tool across a small company.
I would've liked to have used the defect tracking tool that is integrated in QC but business wise it didn't have scope the company was after.
With ontime we can track Incidents from our clients, track Features that will be included in upcomming releases and keep track of Defects or Issues.
Testing wise Basic defect workflow is:
1. Find a defect while running our tests in QC.
2. Enter defect in Ontime.
3. Take Ontime Defect ID and enter it against the failed test in QC.
4. When defect is resolved move Defect ID in QC to history.
5. Then close defect in Ontime.
The process is the same for Automated and Manual testing.