You will still be able to use content permissions feature through Press Permit, but with better support for third party plugins which usually won’t be compatible with Press Permit’s custom user groups. You may want to use the Multiple Roles Plugin in future in addition to Press Permit.
Once you have converted the member’s groups to roles and stopped using Press Permit’s user groups, you may safely uninstall this plugin and won’t need it anylonger.
Conversion process works with unlimited amount of members in your database and will not break when browser window may be closed – just reopen conversion page and continue.
You can download latest version on WordPress Plugin Repository.