[Spire of Coagulated Globules] vs [Kiril, Fury of Beasts]

[Clefairy]

Go download mew and punch in your stats with both weapons, remember to include the armor and to check/uncheck the box. Set it for tanking, look at the damage taken information it spews out. You'll quickly see which is better.

Bonus armor isn't affected by any multipliers (or, it hasn't ever been, so it likely still isn't) is just 700 armor straight up, which outweighs most the mastery loss. The proc is just a bonus.

[Arielle]

H Kiril > H Spire >= Normal Kiril > Normal Spire >= LFR Kiril > LFR Spire.

The ">=" is because they are within the variance range when simmed for overall damage reduction.

Edit: lol EJ

[tangedyn]

Using AEPs from my spreadsheet for my own profile, my numbers agree with Arielle that H Spire is just slightly better:

H Spire:
+75 agi * 1 = 75
+52 sta * .1655 = 8.606
+409 mastery * .4935 = 201.8415
+160 hit * .1321 = 21.136
+106 dodge * .7975 = 84.535
Total AEP value = 391.1185

Kiril procs about every 60s, so...
Average Agility over time = (10 * 107 * 5 + 10 * 107 * 10) / 60 = 267.5
N Kiril:
+700 armor * .1593 = 111.51
+267.5 for proc
Total AEP value = 379.01

[Angron56]

seeing the same as tang, also while you're comparing one item against another item it's easier to tell which is better, but it's not like there's an abundance of mastery on 410+ leather. might want to take into account your own gear situation depending on the fights you're tanking.