For 700 I like rail...
For 550 radix
For stock 450 edge

Citizen#024

 

I think it depends on your preferred flying style. For me i try to fly fast 3d and i find that EDEGE are very aggressive and work well on high powered 500 - 700 class helicopters. If your heli does not have the intestinal fortitude to take advantage of the aggressive blade, it will bog. For 450 size i like a protos stretch using align 360s.. the align are not too hard and offer a nicer feel for 3d...