Register Plus seems dead. It has not been updated for almost two years and its author does not respond to queries. This plugin looks like a good potential replacement. I'm glad to see it has been recently updated.
What I miss most in Cimy User Extra Fields is the ability to approve new users. RegPlus used to offer this but that was buggy anyway (easily bypassed). If Cimy User Extra Fields would offer something like that, it would definitely be the plugin of choice for complete user management.