Please take into account that there seems to be lot of Trait interaction with the boons and Traits are currently a black box we haven’t got a good look at. Boons are also a little more complicated that conditions.
|– Vigor – does increase maximum health|
This boon increases maximum health. Unlike in the original Guild Wars, no health is lost when the maximum health returns to its normal level, although the health is still capped to the current maximum health. The Elementalist has no skill or (known) trait right now that will apply this boon to him/herself or allies. The Ele is in good company with the Thief, Ranger and Necro, who also lack that ability. Guardians shine at creating all sorts of boons, they even have their exclusive ones. Warriors & Engineers can create a limited number of several boons.
|– Regeneration – heals for a small amount of health over a certain length of time|
When this boon stacks, the duration of the healing is extended, but not the amount of healing (according to the wiki). Currently it is unknown, how this information relates to the consumable regeneration boons you could buy at different potency levels at the last demo. This needs to be clarified in the future.
The Elementalist has three skills that create this boon: Healing Rain, Glyph of Elemental Harmony (while attuned to Water) and the aquatic Heat Wave. The trait “One with Water” will also give yourself this boon (10sec). While you are attunened to Water, your nearby allies and yourself have the benefit of the regeneration boon (at least that’s how it looks like on a Gamescom demo video you can find in the media thread).
|– Swiftness – increases movement speed by 33% (passive effect from signet skills only 10%)|
This is the counter-mechanic to the cripple & chilled conditions and it lets you reduce its effects (17% or 33% movement reduction instead of 50% or 66%). Removing the condition will always be better than compensating with the boon. The Elementalist has four skills that can create this boon: Updraft, Windborn Speed, Glyph of Elemental Harmony (while attuned to Air) and Signet of Air (10%). The trait “Haste” grants the Elementalist swiftness when he/she is attuning.
The Ele is on par with the Guardian at granting this boon. They share the number one spot among all professions.
|– Might – increases damage|
This is the counter-mechanic to the weakness condition, which decreases the damage potential. The Elementalist has just one skill that creates this boon: Glyph of Elemental Harmony (while attuned to Fire). The trait “One with Fire” grants a 10sec might boon after attuning. Almost every class has one or two skills that grant the might boon.
|– Protection – improves defense|
This is the counter-mechanic to the vulnerability condition. If it works like the swiftness boon, removing the vulnerability condition will be the better option to try to counter it with the protection boon. The Elementalists has several skills that can grant this boon: Glyph of Elemental Harmony (while attuned to Earth), Ring of Earth and Signet of Earth (passive effect). The trait “Improved Armor of Frost” also grants protection to nearby allies, when the Elementalist is using that skill on him-/herself. While active Earth Attunement itself grants a protection boon to the Elementalist.
Only the Guardian has more options to grant protection boons than the Elementalists.
|– Fury – increases your chance to score a critical hit|
There is just one skill that applies this boon acording to the GW2wiki: Signet of Fire. The Gamescom demos also show a fury boon on the Elementalist whenever he/she attunes to fire. Warriors are the main source of this boon in the game. The only other way the Elementalist can increase its chances to hit critical are weapon & armor upgrades or an attribute concentration on Precision.
Switching attunement a lot will grant you more boons than just sticking with one element, as many are toggled on with the switch action. The use of the signets also rewards you with boons, because you miss out on some skill diversity by sacrificing utility skills slots. On paper, the more defensive elements of Water & Earth have more boons and together with the passive signets should make you very durable compared to the aggressive Fire & Air abilities.