The Magician's Tower

Is vapor core better now since the crit damage effects our rains, unlike fire core?

If you're in a raid setting and getting adps, no. Fire Core + First Spire + black wolf or IoG > Vapor + Elemental Union + First + black wolf or IoG.

What about if your not raiding, hence lacking all the adps?

In group content you will get slightly better results when using First + Elemental Union + Vapor Core vs Fire Core + First. Just remember that you have used union, so you have a shortened "burn" period. Also, Vapor Core alone is greater than Fire Core. These do not include first spire, just Vapor vs Fire.

This is with our weave of RS>Rain>Rain>Spear in group content. If you need to remove rains and instead use more spears/bolts, than the results may be different.

Just to let you know, Vapor Core/ IoG cannot be on at the same time. This could be a bug, but right now, just tested, they do not stack.

Heh, was quite tired early and forgot some things, kind of. You asked about vapor vs fire core, and I answered that. But, if you want to get max dps in the group environment, completely independent of modifiers from others, you will want to use Fire Core + First Spire + Glyph of the cataclysm, instead of Vapor Core + First + Elemental Union. Cataclysm is a critical damage modifier of 160%, while Vapor Core is a critical damage modifier of 126%. Cataclysm will be used in lieu of Vapor Core when modifying rains (the only reason we would use it over fire core), since only the highest critical damage modifier will be utilized. Therefore, if you're not burning a glyph in group content use Vapor Core + Elemental Union + First Spire; if you're using Glyph of the Cataclysm, use Fire Core + Glyph of the Cataclysm + Fire Spire of the Elements for highest dps (glyph + fire being higher than vapor + union at the cost of 5 AA).

Thanks Ill keep that in mind.

Though sadly nothing in the group game is worth a glyph.
Heck, with just my chanter and mage, nothing is really tough (aside from events made to have pc tanks with tons of unmezzable, unrootable, unstunnable adds)

With enchanter you get IoG, which is much better than Glyph of the Cataclysm.

ahh, illusions of granduer. I wasn't sure what you meant by IoG

Critical Damage modifiers:

Vapor Core: 126%

Glyph of the Cataclysm: 160%

Group Black Wolf: 200%

Illusions of Grandeur: 250%

Since only one will be utilized, if you have Illusions of Grandeur you don't need cataclysm or vapor core, since vapor doesn't stack (even if it did wouldn't matter), so just use Fire Core.