After reading the very interesting thread in these forums about the aggro generation of Thunderfury my guilds MT started using the sword again after a lengthy time in the bank gathering dust. I am the guilds main offtank and have always used The Annihilator due to its sunder stacking bonus which does indeed help a bit with damage.
Whilst offtanking Chromaggus I was able to pull the aggro off the maintank after two minutes of fighting, we both thought this was strange and sought to investigate our findings.

Here is what we found:

Using KLHT threat meter, myself and the MT went to Blasted Lands to take on the unkillable Giant - a fair fight as we could generate infinite stats.
At the same time we started Proc Watch to accurately work out the frequency of each weapon's proc.

Fight1: MT started building aggro for 30seconds before I started. At a rate of 19% procs he held aggro for 1min 24seconds before I took aggro with just auto attacking and a proc rate of 29% on my axe. KLHT threat meter pointed to threat generation well above my white damge.

Fight2: I began the fight this time, again for 30seconds before the MT started. My axe was ona proc rate of 27% this time with the thunderfury reaching just 17%. I never lost the aggro on this fight and once again KLHT showed a significant amount of threat was generated by the axe' proc.

This probably isn't conclusive but it is certainly interesting and has made our MT rethink his TF usage.

Banking Thunderfury as an MT confuses me greatly. What was he using instead? Do you not like having mobs hit 20% slower?

Anyway, it's certainly possible that the Annihilator proc generates as much threat as a sunder or something, in which case it'd certainly generate a lot of threat. But you're giving up so much over epic tank weapons, let alone TF, to use it.

Indeed but he will be in 6/8 dreadnaught withina few weeks which will give him the 440 defence and high stam he needs, it does seem to defy belief that a blue is so good though. Oh Praetorian he was using Bloodlords defender instead as he took a defence loss in other item slots In AQ40.

You misspelled the weapon's name.

Annihilator (41.5 damage per second)
Chance on hit: Reduces an enemy's armor by 200. Stacks up to 3 times.

It seems that chance on hit has a lot of threat.. Maybe Blizzard thought no one used it (never seen it been used), and so never noticed that the proc has a lot of threat with it.

Another interesting argument I forgot to add is that although the mob attack speed reduction of TF is awesome we ended up making on of our 5 DPS warriors use 5/5 Conquerors to amke thunderclap a 15% speed reduction. This when you consider TF is a low 15-20% proc chance is far better for heal rank2 spamming guilds as it keeps a constant reduction in damage as opposed to a proc reliant 20% reduction.

Thanks for the spelling help too:)

I doubt Annihilator generates a lot of extra threat. One of my guild's tanks uses it - I've still managed to pull aggro off him after 5 sunders/an Annihilator proc (note to self - do not use thistle tea within 5 seconds of attacking). The proc is pretty rare as well, and the axe is really expensive. I don't think it's worth the cost of the Arcanite, and definitely not worth using over Thunderfury. It does increase melee DPS a bit when it procs, but the proc is just too rare to make it worth it.

I don't get it.

I dont mean to be rude but this is not the way to dispute someone's test results. We really need someone else to try this out and get a larger sample.

Earthfury five piece EARTHFURY EARTHFURY EARTHFURY

Well, if it really is about a 30% proc rate and the debuff is generating ~200 damage worth of aggro, it's generating an average of 60 extra threat per attack. That would be quite a bit of oomph for a blue.

My issue isn't the fact that Annihilator possibly generates more threat due to an abnormally high procrate -- as Gurgthock mentioned, it's the fact that you would bank TF and/or use Annhilator in place of it regardless. Is threat generation that big a deal for you that you need to use this?

Wodin: Forgetting about the minor stats on TF, giving up a 20% slow and using a ~41DPS weapon in place of a ~85DPS one seems a bit odd -- unless as I mentioned you're really having aggro issues to the point that you need the relatively marginal improvement that Annihilator would give (supposedly).

To the OP: Are both of you spec'd the same? How about gear? Additionally, was this just over 2 fights or have you done anymore extended testing? From everything I have heard up to this point the proc rate on the axe was quite low, so 30% is surprising.

Even given the ~30% proc on that axe, I find this more than strange

Just stating my experiences. I'm not saying he's wrong, just that it seems unlikely.

I think you should test on a mob that doesn't mitigate most of the nature damage from the TF proc.

Here is what we found:

Using KLHT threat meter, myself and the MT went to Blasted Lands to take on the unkillable Giant - a fair fight as we could generate infinite stats.
At the same time we started Proc Watch to accurately work out the frequency of each weapon's proc.

Fight1: MT started building aggro for 30seconds before I started. At a rate of 19% procs he held aggro for 1min 24seconds before I took aggro with just auto attacking and a proc rate of 29% on my axe. KLHT threat meter pointed to threat generation well above my white damge.

And how many procs did you each get during that 2 minutes? The frequency of the proc isn't nearly as important as the actual number.

So...did this proc rate get stealthbuffed?

Bah. 12 arcanite. Time to get farmin I suppose.

anyone know exactly how much of a dps increase -600 AC to a boss would be to physical classes. this is looking very temping to me.

Similar free weapons that can also be offhanded.
Rivenspike - http://wow.allakhazam.com/db/item.html?witem=13286
Bashguuder - http://wow.allakhazam.com/db/item.html?witem=13204

Gear makes a huge difference. If you're comparing the threat generated by a Protection warrior with full wrath in defensive stance to, say, a fury warrior with Defiance and the best DPS gear through AQ40 in Defensive stance ... the Prot warrior isn't going to have a chance simply because of the DPS difference.

It's worth noting that the effect on those two weapons (Puncture Armor) differs from that applied by the Annihilator (Armor Shatter).

-1200 AC from the debuff bitch warrior anyone? :D

That does sound pretty interesting. I wonder if it's worth giving up one warrior for that set of procs.

I'm actually sort of amazed that this would even come up. I'm so amazed someone would tank with Bloodlord's Defender rather than Thunderfury... Do you have multiple TFs in your guild, or something? TF in the hands of a skilled tank is the highest aggro generation in the game, the best proc, and is absolutely a no brainer.

Could you argue that the Annihilator might be useful in the hands of an OT for increasing physcial DPS on certain fights? I think that's possible, and might be useful for testing - if it is a good aggro weapon, so much the better since we're talking about an OT here. But, honestly, if your MT is using TF and has a spec that includes defiance and either flurry or shield slam (with prot generally considered to be better for long term aggro, if nothing else), it should NEVER come up that ANYONE could pull aggro on a fight like Chrommagus, where the MT has a lot of rage and tons of time when he is the only person attacking.

Actually, I'm amazed I spent this much time considering a pretty simple question...

/me goes back to longing for a Thunderfury (which I wouldn't be banking)