9th.
Lasts one round per level, gets you an additional action every round, including attacks? There's no level at which it ISN'T an obvious choice for anyone who gets only limited spells known.
If everyone who could get that spell wants that spell, it's overpowered. I've seen sorcerer-players agonize about fireball and displacement and stinking cloud, but I've never seen one pass up 3.0 Haste, except for purely roleplaying reasons (ie, "Nothing but fire spells").
Lasts one round per level, gets you an additional action every round, including attacks? There's no level at which it ISN'T an obvious choice for anyone who gets only limited spells known.
If everyone who could get that spell wants that spell, it's overpowered. I've seen sorcerer-players agonize about fireball and displacement and stinking cloud, but I've never seen one pass up 3.0 Haste, except for purely roleplaying reasons (ie, "Nothing but fire spells").