they don't matter unless they do
for a sorcercer that likes Magic Missile a +4 is fine, you can use the feat to grab a Worlock hex and cantrip [assuming you don't carry Will] but one that likes debuffs \ stuns will want the +5 because then the bad guys get a save and you want them to fail it... overall Cleric and Bard are the classes that normally debuff and Sorcerer is a damage class but you get the idea
