RE: Which micro heli?
the BR/MM helis are always slow. because of the rotor design, any forward motion is counteracted by the rotors and the heli tries to correct itself and go back to a stable hover. forcing it into forward flight with the tail prop is basically making the heli do something its not actually designed to do, which is why they're slower than the other micro helis.
there are a few ways to get some faster speed though. using a larger prop thats meant for a 4mm motor, something like the piccoZ tail prop, can help. the AA prop is far too big and will actually slow the tail motor down, giving even less thrust, despite the prop being much bigger. you can also add a bit of tape to the blades of the tail prop to give it more area and more thrust. another option would be to swap out the short can 4mm tail motor that the MM and BR uses for a long can 4mm motor like the piccoZ tail motor.
a recent idea was used to add 4 magnets to the rotors, 2 on the top rotor, 2 on the bottom, placed so that they repel eachother. this way, when the heli goes forward and the rotors get close to eachother, the magnets keep them from either clashing or slowing the heli down. i havent gotten a chance to try it myself, but i've seen videos of the mod in action and it seems to help quite a bit.
the BRII is the normal size BR, 3 channel, with a 12 or 13 inch rotor size (cant remember exact size off hand). they're more stable than the MM simply due to the size of the rotors creating more gyroscopic forces. i think they go a little faster than the MM, but the motors tend to burn out due to the amp load they run at. the mini BR is slightly smaller, with 9.5" rotors. its two channel, forward speed is set with the CG like the piccoZ, but with its smaller rotors, the motors last quite a bit longer and flight times are longer.
nick