if you enjoy not pressing more buttons that absolutely necessary, i would go with spire
if you enjoy stacking your buffs and cooldowns to get 50000+- attack power for a 10 sec window when shit absolutely must die, and also desire to be monstrously large on the madness of deathwing fight periodically, i would go with KIRIL (edit i typed spire again -_-)
TBH the reason i chose kiril is because i was the first in our guild to get one so i wanted to flaunt it at the bear tank while i could
I had a very similar problem before, deciding between using kirils raid finder version vs heroic ranseur of hatred (391 firelands polearm), going by female dwarf it said i would gain around 150 dps (IIRC) as survival, but was a dps loss as BM (i switch between BM and survival for buffs since we're 10man), i decided to use ranseur, i annoyed me how much secondary stats i would lose for a proc, i prefer the static bonus from stats on the firelands polearm.
as said above it is personal choice, it is definately a good a weapon, im using the normal version now, but id go with the spire.