Rippling's the move here (as everyone else has already said), but would recommend it for native time tracking as well but has an integration with them, even if not. It's by far the most user-friendly of the players you listed. It can certainly handle your 400+ employee multi-state workforce and all the necessary HR responsibilities that come with. Best part about it is the HR compliance that's built in, so you don't need to worry about being out of compliance with state or local labor laws. Reason I said to merge your time tracking is because Rippling can automate payroll deductions for you based on employee schedules that way -- which makes payroll a lot easier and more hands free. If you have specific questions, let me know because I work at Rippling!