Movement and attacks with haste

[Gromm]

3) Taking less time to cast a full-round or longer spell makes perfect sense, especially if you view haste as speeding you up and not simply "adding another action".

It also avoids situations like "I cast Summon Monster, ok I still have a partial action left, so I (attack, move, cast another spell)."
Only his spells still not complete.

And haste has always favored spell casters. Lets see one more attack or one more Disintigrate? Which is going to be better in the end... hmmm.....
An extra attack means little in the big picture, whereas 2 spells a round can quickly decide a fight (even at lower levels, especially at high levels). There's a reason characters get more and more attacks in a round and spell casters are always casting one spell.

 

[kreynolds]

And haste has always favored spell casters.

Although, everyone seems to forget how common Haste and Haste-like effects are and how readily available they are to the masses, whether it be through potions, scrolls, boots, bracers, weapon enhancements, armor, or spells cast on comrades, and there are even the few PrC abilities. Taking that into context, I don't think it favors any one class over the others, but that's just my opinion, I could be wrong.