Originally Posted by
Pandjed
Most universal enhancement trees don't work well as main-trees, because they're either too weak (and therefore outdone by class-trees) or too specific in what they do (and therefore don't synergize well). Often both.
Remember, that all of these trees may be unlockable, but all but one are hidden behind an expansion, which favor you need to unlock it. So if you want to stay F2P, you won't get any of them, and buying them directly is kinda a waste, if you can get the expansions instead, that also offer the quests (and Ravenloft, Sharn, and Feywild also grant great gear).
Falconry, otoh, need a lot of adventurer packs to unlock and you even need to run the titan raid, which is seldom run. So this one, I'd just buy.
Harper: The only redeeming quality is the INT to hit and damage, and Know the Angles (a battle trance). Otherwise, this tree is way too weak and have no real direction.
Vistani: This is the best secondary tree for rogue assassins, throwing builds, and specific other niches (like Keeper of the Crimson Covenant [special weapon] paladins and such). If you have a bunch of points left, you can grab Haste boost here, the best action boost in the game.
Falconry: This tree is a nice secondary tree for wisdom based characters (such as monks, clerics, and some ranger builds) that want to do weapon damage. It comes with a lot of cool things up to T4 and T5 is certainly good, just usually not as good/fitting as most class T5s. But you can get WIS-to-hit/dmg, a wis-based battle trance, and +5% quality hit points. Add that to regular fortification bypass, +helpless damage and the debuffs that makes enemies helpless, this is a really stable tree. Probably the best balanced tree so far, and the best option for bow-focused monks imo.
Inquisitive: This is the only tree that works as main-tree and it's probably too good. As an universal tree, you can still get full benefits as a multiclass character (therefore many take 2 artificer levels to keep a runearm in the off-hand) and it just demolishes your enemies. Slap this on any class, and you get a great ranged DPS class out of it, plus whatever your class provides otherwise.
Illusionist: Here we have CHA to hit/dmg (no battle trance though), either for every weapon or by conjuring a shadow bladde (which can be helpful for tankbuilds while leveling, if they don't want to use a lesser heart instead to level up in a more offensive build). Core 3 gives a great crowd control. Overall, it's nice and stable, not really special, but until recently, it was the best friend for caster clerics (as cleric trees are bad, though with the updated damage of certain spells, divine disciple took off again), and it can still serve as a nice (though not great) offensive caster tree, if you want to play something that doesn't have a decent option you want to take,
But I personally see it just great for the cha-hit/dmg and the core 3 crowd control.