RE: Is Vbar worth the added expense?
The Spatan requires you also buy additional gyros for each axis. This also allows for use of a infrared stabilization unit. These sense the temp differential between sky and the ground.
So for three axis you will need a gyro. This will drive up the cost considerably. The gyros need to be programmed for each axis individually from the main unit. It would be difficult to fit all the electronics into a 450.