I swear to God, I'm going to start a thread titled "STOP SUGGESTING WORDPRESS FOR SHIT IT'S NOT MEANT FOR."
WordPress is not a user manager. Just because people can sign up and leave ratty little comments on blog posts does not mean it properly handles accounts and account information. Let alone handles them SECURELY.
How often does this topic come up, which CMS to use? And why, 99% of the time, there will be a boatload of people suggesting WordPress for something completely ass backwards from WordPress' functions? WordPress is not a CMS, it's NOT FOR THIS.
To do this, you'll want something like Drupal or Joomla. Something established and SECURE. There's a very important keyword in this thread that tosses WordPress out as a suggestion, "account balance." Which means you're most likely dealing with managing users' money. Which means WordPress would be the worst mistake of your life after every user is suing you for compromising their financial info.
(funny true story, right now on a web design forum I frequent, people are going haywire trying to deal with their WP sites getting hacked. WordPress has way too many unstable security flaws for this.)
That said, please, please, please do NOT use WordPress for this. Go with either Joomla or Drupal.. Both are very stable, dynamic, secure and with established extensions that enable them to do just about anything you want.
in CMS (IMO), you have 3 choices...
1. WordPress.. This is the 'cute' brother who has lots of friends and gets along with everybody. He knows how to do some things, but mostly those things are how to make his hair look pretty and matching his shirt with his socks.
2. Joomla.. This is the middle brother. He gets along with some of WP's friends, but him and WP don't hang out with each other. While Joomla CAN style his hair like WP and look good.. It takes him longer to get ready. He's not as pretty as WP, but if they got into a fight, Joomla would beat the ever loving shit out of WP with no remorse.
3. Drupal.. This is the weirdo. He's like 40 years old and just hangs out in the basement lifting weights. He's faster, stronger and smarter than both WP and Joomla. However, he's not friendly and even if he spent months getting ready, he usually doesn't look pretty. But he DGAF because he doesn't care. He's one of those "I wear a fanny pack because it's functional" guys.
In the end, it all depends on what you're going after. If you want a pretty website that doesn't know how to do anything except be a pretty website, you want WP.
If you want a pretty good looking website that's capable of advanced features, user handling, everything WP is capable of and much more. You want Joomla.
If you don't give a fuck what your site looks like, but you want the best security and richest functionality, you want Drupal..
That is current CMS in a nutshell.