I just did a comparrison on the Javascript Calculator between 2" Blazers and 4" feathers using the arrow I shoot ( Terminator lite select 26.5" with 2" Blazers and 100 gr. BH ). Here is what I got at 40 yds.

Blazers: -46 vert. drop 242fps 50 KE .413 Momentum

Feathers: -49 vert drop 231 fps 46 KE .395 Momentum