I'm in the camp that the rogue is the clear stand-out. They're effectively doubling their total damage for the round while the fighter is theoretically +50% (2 attacks + 1) but in reality probably less as they have a limited amount of Battlemaster Dice, so all it's doing is moving some damage up from a later round. If and only if the Moon Druid is in a form with a single large attack are they worth it - their AC is so low that the +2 isn't as big a difference.
After that - absolutely no one except in corner cases like needing movement for a chase. Save it for another battle, use Concentration for something else, save the slot, whatever.
But wait, let me check Soulknife...
Ah, they are gimped in terms of opportunity attack. They can only manifest their blade on an attack action, and a bonus action after an attack action assuming your other hand is free. So they are left with no weapon in hand to attack on someone else's turn. So they would need to carry a normal weapon in their other hand, which loses out on their bonus attack. Plus they can't use things like Homing Strikes with an opportunity attack. Wow, this may be the worst rogue subclass to take advantage of haste.
I guess the best way for the Soulknife to take advantage of haste would be either:
1. One hand empty, other with finesse or ranged weapon. Steady aim bonus action for Advantage, but no movement allowed. Haste action attack. Normal action Ready to attack after whomever goes next.
2. (Drop dagger being held.) Both hands empty. Haste attack. If miss, bonus action psychic blade attack to deliver SA. (If hit, then used BA in whatever way makes the most sense.) Free action draw weapon, likely dagger for finesse & range. Assumes a bandoleer with a bunch of daggers on it, which is common in D&D art. Because every round you'll be dropping them to have both hands free.
