If you have fields created by Profile or Content Profile modules this module ignores them even if they are required for registration form.
The new user gets empty requered profile fields or no profile page (content profile).
It would be great if this module honor profile (content profile) fields and allowed them to be synchronized with mail.ru info (First name, Last name, Date of birth).

It also ignores User Registration settings.
If "Only admin can creat new users" is set the module still allows user registration.