I used the brushed tail motor with a HH gyro with a brushless main motor at first. The extra torque of the brushless motor was difficult for the small tail motor to keep up with. Hard collectives would cause it to rotate CCW. Eventually the tail motor failed (and the Axe crashed) and I upgraded it to a brushless 10 gram outrunner. It works great. The outrunner has magnets on the outer area of the motor that rotate. This weight must be accelerated and deccelerated quickly. I would think an inrunner would be quicker to respond to power changes than an outrunner.

I don't remember why I went brushless to begin with. The stock main worked just fine, although it doesn't have as much power. If you really need to save money, I would stay brushed and stock on the main motor and go brushless on the tail.