In my opinion...

The blazers steer broadheads equally well as the 4" vanes. I shoot them exclusively.

The advantages to the blazers are:
1. They are darn near indestructible. I have shot them through everything from deer to targets to dirt with no damage.
2. If you shoot a whisker biscuit, they will not warp from the constant shooting through the WB bristles

The disadvantage are:
1. They are a little taller than 4" vanes so they may create some clearance issues while slipping past cables/rests. If this happens, the issues can usually be resolved with a different cable guard or rest adjustment.
2. They are also a little more difficult to fletch with a nice helical. I don't hear this disadvantage discussed much but their stiffness does not lend itself to being wrapped around the shaft. When I fletch, I leave the blazers in the jig a few extra minutes to let the glue completely set.