This is your answer, right here. ACF is so flexible that you can do really simple stuff as well as deeply integrated tasks.
If you need to have you or your users post from the front end of your site, this is the ONLY plugin solution that works. Few headaches, amazing support, and great (ever-improving) design.
Plus, it's great if you just want to use it on the back-end to add extra fields to your posts/pages/etc. SUPER easy.
If I could give this 6 stars, I would.