Neonchameleon
Legend
They don't - they give you the same powers at level 1. In other words the ability to cast one spell per short rest (which might be different) and an unlocked Eldritch Blast. Opening your magic up is common. At level 2 they then give you a Pact Boon - and this won't necessarily be the same. And only by level 3 do they actually change you.Kind of weird that the devil gives the same powers as an angel, gives the same powers as a weird sword, gives the same powers as Lovecraft's sloppy seconds.
The thing that's in common is the "Ye'r a wizard ... sucker" starter. And even then the spells aren't the same.