Some users can easily uninstall the spyware that they are using.
No matter how complete the feature of the bluetooth cell phone spy that you have, if that can be detected by the users then it is worthless. They can simply uninstall it and you will not be able to track if they are using their phones for malicious activities. That is the challenge for all manufacturers of bluetooth cell phone spywares. They should have a device that can track ALL the cell phone activities PLUS they need to make sure that their software can not be detected.
Other bluetooth cell phone spies are very complicated to use. I know you can be pretty busy with all the works in your office, not to mention the pressure that you have at home. If you are going to use a bluetooth cell phone spy that is complicated, then that will just add up to your burden right? Choosing the best product means that you can instantly use it without going through thick manuals.