According to the user guide, users should have the ability to add their own password in versions 2.7 and above:
"NEW in 2.7: You may add a password field via the field management panel if you would like
users to pick their own password at the time of registration."
However, this does not appear to be working. I added a password field to the list of fields and I can see it on my registration form. But when I submit my registration with my own password field, the following behavior is observed:
1. The password is not stored in the normal "user_pass" field of the wp_users table. Instead, the usual randomly generated by wordpress password is placed there.
2. The password I input on my registration form is instead stored in the wp_usermeta table with a meta_key = "user_pass" and a meta_value = the password I chose on my form in CLEAR TEXT.
3. I am unable to login successfully using the password I input on my registration form.
4. I did not try because I don't have the email confirmation setup, but I would assume I would be able to login successfully using the randomly generated password from the wp_users table.
In summary, it does not appear that WP Members is treating a user chosen password as a native field and therefore it is not usable by the native login process.