I'm also using Torque Pro with my cages, and would highly recommend it for reading fault codes, monitoring sensor data for troubleshooting, or just for having a configurable extra gauge cluster on any OBD-II compliant vehicle. Now while Torque Pro works with the Rocket, it only allows you to access the standard OBD-II diagnostics data set. TuneECU has much deeper integration with the Keihin ECU, and in addition to accessing all sensor data, it allows you to alter the fuel and ignition maps and perform various calibration procedures specific to our bikes.
If you just want to add a configurable extra gauge cluster to your Rocket, Torque Pro is probably the way to go. For servicing and diagnosing the bike, Triumph owners are lucky to have a superior tool in TuneECU.