I have this Great Axe for my WAR and I must admit, its pretty sweet. There are maybe four Great Axes better then this in game.
1.) Bravura (Relic)
2.) Abaddon Killer (Stage 4 Relic, has higher DPS with + DEX and VIT)
3.) Perdu Axe (When Latent is active)
4.) Toporok+1 (has higher DPS with + DEX and VIT)
5.) Byakko's Axe
6.) Berserkers Axe (Hi DPS but with no extra stats)
This is just a rough list but you can get a general idea that the Byakko's Axe falls high on the list of nicer great Axe's until you can get any one of the four above it. The Byakko's Axe is also much easier to get then any of the top four I listed. I would say that the killer effect kicks in about <15% of the time. Either way, with this GreatAxe, my Steel Cyclone damage hits for about 1500-2000dmg with SA, berserk, warcry, aggressor, and 300%TP. Makes for an awesome show.