multi blade heads are mainly used in scale, you loose 50 points a round for having a flybar head. They also seem to work best with a flybarless system like Skookum SK360, VBar, or Helicommand and the like.

3D guys fly 2 blades w/ a flybar or two blades with a flybarless system.

The only advantage of a multiblade head is it looks cool. Its expensive and a good bit of work and tinkering getting it flying good.

If you're looking at nitro helis don't get less than a 7 channel radio, among other limitations the 6EX 2.4 (a nice little radio, I have one) lacks sub trims and you'll want a governor channel at some point and for that you'll need 7. The 7C 2.4 and DX7 are both nice radios.