Custom Post Type or Custom Tables

I am in the process of writing a plugin that allows end-users to submit a form that includes customer information. Upon submission, I am notified that a new customer has submitted the request form. If I approve the account, I am going to create a WordPress user account.

I am at the beginning stages of this plugin and want to know if I should use custom database tables to store my user information, or if I should go the route of just simply using a custom post type and adding meta-data to the post type?

UPDATE:

Wow, down-vote already! Anyway, an update to my question, let me word it this way…I have now attempted to create a custom post type of customer, and for customer, I wanted to only have a meta-box that contained First Name and Last Name. When I did this and disabled all of the supports options for the custom post type, it was a nightmare listing the posts due to the missing Title value. It would always set the Title to “Auto-Generated” and that doesn’t work for me. I ran into this GREAT Plugin (super-cpt) that makes the creation of custom post types and meta-boxes a breeze.

So, I’m not so sure custom post types will work for me since so much custom UI work needs to be done to convince the front-end and admin dashboard to work for me. I’m leaning more and more on custom data tables but would like more info on customizing the edit form for a custom post type. Anyone have a link they could share?

I don’t know if we are allowed to link to other answers but there is another question very similar to yours and the accepted answerer stated these things:

You should be skeptical of anyone who says that there is a single
“right” way. The right way depends on the situation. Using the CPT
infrastructure has a number of notable benefits:

• You get the Dashboard UI for free
• You automatically take advantage of WP’s caching, including any persistent cache plugins that the installation may be using
• You automatically get goodies like post revisions
• You get access to the WP_Query class, which means that, in theory, you don’t have to write any (or at least not much)
  likely-to-be-buggy-and-vulnerable-and-inefficient SQL

If you’re planning on distributing the plugin or opening it up for
open-source development, you may find that developers are more
comfortable using custom post types and the associated API functions
than your own custom stuff.

source: Here