Dreamstate, I think a few people in this thread have mentioned it's one of the less useful of the mana regen talents for druids.

That or intensity, either way, I've got neither and have no mana issues, though I do have a good crit rate via my gear

I think GC even said as much - that the check whether it's yours or not might not be done properly.

His latest post (emphasis mine):
It confirms that if you gain the bonus from someone else's FF, it's not intended.

Not that the comparison above is a key point, but it made me curious.

What advantage does E&M have over Ebon Plague to lead to such a strong opinion? I'm aware of these differences:

Ebon Plague has a longer duration, but E&M is reapplied more frequently.
Ebon Plague is AE, thanks to pestilence, while moonkins don't apply E&M at all in AE situations.
DKs start their dps off with a disease, while moonkins generally apply IS and MF first, with the first wrath landing 4-4.5 sec into the fight. (pretty minor, but if you have 8 caster dps doing 5k each it's an extra 20k damage or so, though that's pretty rough math since that's also during rampup time while people are applying debuffs to start the fight).
E&M has longer range (30-36 vs 20). Not sure if this matters on any fight. Perhaps 5-minute Malygos.
Ebon Plague can be applied with an instacast, so you can refresh it while moving (not really sure if there's any fight where this is an issue, unless you're inexperienced with Heigan).

The AE thing is obviously pretty nice when applicable. The other things aren't really big deals (though I do let E&M drop off bosses sometimes, e.g. Grobbulus, where Ebon Plague's longer duration might allow him to keep it up during his absence).

What am I missing in E&M's favor?

Ghostcrawler followed up and you do indeed get 3% crit regardless of who puts up faerie fire, and feral faerie fire counts as well

So with GCs new post it seems we will get to keep our 3% to crit! iFF (even if you have a spriest to apply the 3% hit) should be a part of every moonkins spec.

I am sure most people had it already, since what testing there was seemed to advocate it working for any FF, but for the few remaining holding out on iFF, you can safely spec into it for a pretty much free 3% to crit.

Depending on the DK rotation and encounter, Ebon Plague may not have 100% uptime. From my own experience, it is very close to 100%, but it's definitely noticeable when it's not up.

I should stress that this is extremely minor-the longest I have seen E&M stay up before it's been overwritten by our DK is around 4 seconds every minute or so. E&M seems to go up and be overwritten immediately quite a bit, but this may because of latency timing between EP being refreshed and my wrath/starfire hitting the bosses.

Right--if there's an unholy DK on your target, E&M doesn't add anything of worth. Fortunately, you don't have to worry about it, as it's a worthwhile personal DPS talent anyway. And there are some situations (such as Sarth10+3) where an unholy DK might be in the raid, but not applying EP to your DPS target.

Vortex ticks every second, and interrupts when it ticks. Since your cast time can actually be lower than 1s (yes, this is incongruous with what I said before. This is the difference between actual cast time and effective cast time), it is very possible to get Wrath casts off during Vortex. That said, if your raid is blowing Heroism at any time where you're liable to get hit with Vortex with it still up, you're doing it wrong. Spider procs would possibly be able to get through it, though.

I wanted to elaborate the term USEFUL for some of the players here with regard to Gale Winds as I have whole heartedly bought into it as well, and for a bit more then trash. My example is:

- Sartharion (+drakes). Very tight DPS requirements here with drakes. If you left drakes up, you should be periodically grouping up the flames/whelps on the rear end of a drake and AoEing, especially at the home stretch. We normally do this on 2D when Tenebron is around 20-10% for the finish her finish and that leaves the board clear until Vesper lands. We tend to group everything up on Sarth's hind leg after a lava wave or every other wave so we are not only cleaning up the adds but getting some effective dps on the boss too. AoE is pretty essential here which even goes above and beyond the term useful.

You must have missed the term heroism "bleed over". No one is casting heroism so we can sneak damage in on a vortex, very laughable that's even assumed. 2 sparks is the driving factor and if its like 10s until Vortex, we will wait. But if we have a good 30s for burn in two sparks, maybe three, we will just hit it and speed along the phase instead of delaying for opportunities that may never come to fruition. Whether I am doing it wrong with that said isn't very debatable. Having done the fight several times and having killed the boss, I'm sure you can agree that a full heroism with 1 spark is not as affective as 30 seconds of heroism with 2 or 3 sparks without having to put the numbers together, meaning there is always going to be some remanent of heroism persisting if you are saving it for ideal spark conditions. Cheers.

well if you want to get down to it, he won't be vortexing anymore if you use it under truly ideal spark conditions, because that would mean you have 4 to 5 sparks that you pop all on top of each other right after a vortex and bloodlust then (and attempt to snag an achievement in the process!! :P).

Got a decent parse today. A bit laggy, and a bit weird since we MD'd Patchwerk from behind the slimes, but should be informative:
Wow Web Stats

I haven't been able to figure out yet if there are subtle differences in rotation (such as when to refresh DoT's, etc.), that are causing DPS differences among people in the 5k range. More parses are always nice.