user information lost by changing forum?

Hello,

Just installed ForumPress asI want to leave buddypress,.. but Iam afraid about the user information.
What will happen with all the user registrations when I delete BuddyPress?

How stand alone are the users in the website so that it is possible to change forum plugin? BuddyPress is to user complex with tooo many steps for an easy to go reaction.

Kind regards of Anne