It has been identified that this importer does work, but it may leave some missing records which may affect certain features in XF, such as editing users.
It is recommended that after importing you should additionally run these queries to cover any possible missing records:
SQL:
INSERT IGNORE INTO xf_user_option (user_id) SELECT user_id FROM xf_user;
INSERT IGNORE INTO xf_user_privacy (user_id) SELECT user_id FROM xf_user;
INSERT IGNORE INTO xf_user_profile (user_id) SELECT user_id FROM xf_user;
INSERT IGNORE INTO xf_user_authenticate (user_id) SELECT user_id FROM xf_user;