Craft - suitability for membership/user registration and document upload/management
Should be no problem, Craft has extensive user management capabilities, check https://craftcms.com/features/users &amp; https://craftcms.com/docs/users as well as solid asset management https://craftcms.com/features/assets

Log in to the demo https://demo.craftcms.com/ or do a local install, as long as your test domain has .dev in the url you can fully test Craft with purchasing a license.