How good is Persistent Blade?

[Zethex]

How would you rate the spell Persistent Blade when compared to other level 1 damage spells? Does it hold any worth next to the likes of Magic Missile? How does it compare to the various rays/orbs?

[Flickerdart]

Persistent blade isn't for damage. It does damage, but what it's actually there for is a flanking buddy that can't be destroyed. Cast it for your rogue, now it's doing more damage than magic missile could dream of.

[Zethex]

But it does 1d4 ongoing force damage vs AC and forces enemy casters to cast defensively. Is that not worth speaking of?

Edit: In theory it does more average damage than a level 1 Ray spell, albeit at a slow pace. Also the damage can continue after the first target falls, avoiding overkill.

[Flickerdart]

Not really. The to-hit on the blade is horrible (your wimpy caster BAB plus only half of your casting stat, against real AC), the damage is horrible, casters can just ignore it and cast normally because the DC to keep casting the spell if it somehow manages to hit you will be lower than casting defensively.

[137beth]

But it does 1d4 ongoing force damage vs AC and forces enemy casters to cast defensively. Is that not worth speaking of?

Edit: In theory it does more average damage than a level 1 Ray spell, albeit at a slow pace. Also the damage can continue after the first target falls, avoiding overkill.

While it can theoretically do more damage than another 1st level damage spell, it does so over a longer period of time than the typical battle (or the duration of the spell,) since it is likely to miss frequently. By the time you are a high enough level for it to last long enough to do decent damage, non-touch AC has outstripped your attack bonus, and any creature it could ever kill would be dead long before it had much effect. You could turn it against a different enemy afterwards, but that requires a valuable action.
If all you are looking for is to damage by yourself, it really is a terrible spell.