Pielorinho said:
I've seen it used a fair amount in the games I run and the games I play in. It's a great spell.
It is an ok spell for certain multi-classing combinations, specifically ones who multi-class as a Sorcerer.
However, it is not really great.
If you are not multi-classed, the damage you typically do as an arcane spell caster is rather limited. Even as a prestige class, this is typically the case unless you are high level.
It also has a major weakness (using the does not totally negate total concealment interpretation) that spells like Obscuring Mist can basically negate it. Since most enemy spell casters usually have a fairly good Spell Craft, this is easy to do (and it is easy to have spell casters inform allies that an opponent just cast True Strike). Even a Wall of Fire can stop it (if you interpret it this way), let alone other types of walls, fogs, or Stinking Clouds.
Even a simple maneuver of hiding behind a wall or large rock for a round negates the spell (for that target).
It can also be wholly or partially negated via other spells, with or without this interpretation, such as Dispel Magic or Mirror Image or Web or Entangle.
It's 2 round duration gives many opponents a chance to do something about it. That something can be as simple as Improved Disarm the caster and then picking up his weapon (if initially within 5 feet of him). Opps, you were not successful due to his +20, but then again, he used up his True Strike to counter the disarm. Needless to say, that was his next attack. Hehehe.
Or Sunder his weapon. Even if not successful, it results in an opposed attack roll.
So, although the +20 sounds incredibly powerful, it really is only one nearly guaranteed hit, that is if your opponents do not react to it. Well, you can often get a hit by just rolling the dice as well. In fact, within those two rounds of casting True Strike, you will often get 1+ more attacks in anyway which greatly increases your chances of hitting than you will get with the True Strike. In other words, while casting True Strike, you are not doing anything else productive.
And, there are other first level spells that are typically more powerful. For example, Magic Missile which averages 3.5 to 17.5 points of guaranteed damage with few defenses. Or Shield which is +7 to AC (vs. most opponents) for 10 rounds per level as opposed to +20 to hit for one attack. Or Mage Armor which is +4 to AC for hours.
And, if you try to use it at too long of range, part of its bonus to hit is absorbed by the range modifiers.
If you try to use it with Power Attack, part of its bonus to hit is absorbed by the increase to damage.
So, yes, it’s an ok spell. It often results in some damage if no opponents react to it. But, it really is not great.
Btw, do not get me wrong. It does have its advantages as well. It is not negated by Spell Resistance or Globes of Invulnerability or Anti-Magic Shields (these latter two if you use a range weapon outside the area of effect). It has an extremely high chance to critical if you roll in the threat range for your weapon (i.e. just like all other bonuses to hit, it applies to both your to hit roll and your critical roll if you threaten). And, in combination with Haste, it loses a lot of its weaknesses.
But, there are many defenses to it, especially since it typically takes two rounds to use unlike spells like Inflict Light Wounds which can often be used in one turn.