I have my S2 member pro set up that when a user registers they choose a custom password. I have found that if they are given a password too many people either do not receive that password (presumably it goes to their junk and they don't have the sense to check it, in fact i'm pretty sure this is the case as I often have the same person signing up multiple times in the space of a few hours, but never logging in or changing their pass)
Custom passwords should eliminate this.
But, I can find no way of sending a "thank you for registering" email with basic details such as their username and the URL for them to login to. Which of course they get if they do not choose their own password
I think it is important that they get this email as it serves as a reminder.
So without such an option I am left with two less than perfect solutions.