do i use directory or membership for this request?

Below I'm including what a client wants me to do. Do I use WPMU Dev's Membership or Directory plugin to accomplish this? It's going to have a searcable database of info for paid members to use. Here is what she needs:

Each person would be able to pay for a membership to the database. The database should then allow the ability to login. This would be a monthly payment. If they have not paid they need to not have acess to the information.