Recuperate can only be done out of combat. It heals HP, heals some moves and makes you regen moves faster.

Berserk can only be done in combat. It gives the same affects it used to (ie, -10% in most skills, vuln mental, +hit/dam). It also gives you a certain amount of HP based on lvl and lvl of whatever you're fighting, by boosting your max HP and your current HP by the same amount (ie, if you're 500/700 and it gives you +80 hp, your hp would become 580/780).

Basically, the change is better in almost every way, except you can't call berserk out of combat anymore.