Haste extra attack and stacking with similar effects

[Xavram5]

Per Haste (and similar language in Blessing of Fervor or Speed weapon) :

"When making a full attack action, a hasted creature may make one extra attack with one natural or manufactured weapon. The attack is made using the creature’s full base attack bonus, plus any modifiers appropriate to the situation. (This effect is not cumulative with similar effects, such as that provided by a speed weapon, nor does it actually grant an extra action, so you can’t use it to cast a second spell or otherwise take an extra action in the round.)"

So what is a "similar effect", other than those 3? I know that the Monk's use of Ki to gain an extra attack DOES stack with Haste and that's been established in the FAQ.

So which other "gain extra attack on full attack" abilities/effects DO/DON'T stack with Haste?

Path of War's stance, Broken Blade Stance, reads as follows...

"While in this stance, the initiator gains a competence bonus equal to his initiator level to Acrobatics checks to avoid attacks of opportunity, and may make an additional attack when making a full attack action. If the initiator is two weapon fighting, he gains this extra attack for both hands. The attack(s) uses the initiator’s full base attack bonus, plus any modifiers appropriate to the situation."

So is this is a "similar effect" and wouldn't stack? Or is it like the Monk's Ki ability, and WILL stack?

Thanks!

[AwesomenessDog]

Divine Power and Blessing of Fervor are the main ones I know of.

Path of War is third party and thus isn't really in the realm of what can be answered here. From what I can understand it's not really a temporary buff like Haste and therefore (or otherwise mimicking/referencing haste like Speed) and therefore it is just an extra full BAB attack in the stance.

The problem comes from the fact that most 3pp content (and much of the later paizo stuff too) has horribly inconsistent wording that makes it hard to tell both what exactly is happening to give you X benefit, but also when that benefit is functionally the same as another source. When you have consistent language, its (much more) possible to gleam designer's intent than if every new time an ability does mostly the same thing, they write it differently or without ordering limitations and other qualifying information in the same way.

That and 3pp is also notoriously unbalanced as drek.

[Derklord]

I assume it's only effects form spells and magic items that don't stack. otherwise, even Rapid Shot+haste wouldn't work...

[Mysterious Stranger]

Don’t forget that a round is 6 seconds long. That does not seem to be that long but in it is longer than it sounds. The round also assumes you are performing multiple feints, blocks and other attacks that have no chance of hitting. Your number of attacks is more of a matter of recognizing and responding to situations where you have an actual chance of hitting.

Some effects speed you up by compressing time or otherwise allowing you to move faster than you would normally. Other effects allow you to perform actions more efficiently or to recognize more openings in your opponent’s defenses. Haste and similar effects are the former so do not stack with each other. Feats like rapid shot or additional attacks from BAB are the later so do stack.

[Xavram5]

oh man, i thought Path of War was still Paizo, just a variant...urgh, didn't realize it was 3rd party stuff.

K...I guess it will need to become a question for my group instead.