@vij You might want to reach out to firstname.lastname@example.org
I don't know their plugin pricing but those features don't sound like too much effort. And if you allow it to be licensed at their will (please be more precise on this, "sell them to others" might be more restrictive than you want to be) it might give you bonus points
I myself don't have much spare time right now, so I'm out of this.
Depends what you want to do... if you want to be notified when user data is updated, then the action hook is fine (if you're not changing anything in the data payload itself).
Useful if you want to take the new user data and update another set of data somewhere else