SmartProfile is a replacement for the XoopsMembers module and the core's user profiles and registration.
It is based on the Profile module in XOOPS 2.2, but where that module was a front to core functionality, this module is self-enclosed and does not influence on the core.
It also means that it does not have some functionality that the Profile module in XOOPS 2.2 has, namely the ability of modules to add new user fields in their xoops_version.php files and use them with $xoopsUser->getVar('fieldname').
However, there is also functionality in this module that was not in Profile, mainly:
1) Much more granular view permissions, you can now set who can view a field on whose profile - e.g. let your webmasters view the real name field of any user, but only let registered users view the field if viewing the profile of a webmaster
2) Registration steps - split the registration process into several steps, determining at which step the user is created
Please note that this module requires XOOPS 2.0.16 AND PHP 5.0x or higher. It also requires SmartObject v0.9.The core user-related files should still work as usual and it is probable that with a few .htaccess rewrites, you can use this module instead of the core's without having to change anything in other modules. I will work on that and give feedback at earliest convenience.