In the last three days we worked at pas.plugins.ldap and its underlying infrastructure. The performance features are in, but we are still reviewing code in order to identify other places where we need to paginate the ldap searches. In the base package node.ext.ldap all work is done afaict.
So I would go with pas.plugins.ldap. We used this for years in production with LDAPs up to 8000 users and 400 groups. If there are any issues left performance wise we can fix them, the formerly known problems are fixed or will get fixes (if any left) in the very next time.
Releases will be cut soon as well.