Use the Locate My Freight app when the driver will stay with the load, grant location, and keep the phone on a data connection. Use hardware when the tractor or trailer has to stay visible even if that phone is elsewhere.
You can run both: phone for the driver workflow (status and POD) and hardware for the asset. MacroPoint is a separate tracking provider some companies already use; this site sells Locate My Freight tracking, not that integration.
See GPS hardware and prices.