Simple_form or formtastic: which one to choose?

I've been spending some hours searching for useful Rails gems but I still hesitate between simple_form and formtastic.

I know they look really similar but I really don't know what开发者_开发问答 I have to choose for my new project. I'd want it to be customizable enough concerning HTML / CSS but still very complete (I have to use bitmask checkboxes).

What can you advise me ?

Thank you in advance.

Both are powerful enough, but if you really want customizable HTML/CSS, simple_form is a bit easier to use. formtastic already groups and adds a bit of style to your form elements, and it's not always easy to customize.