What is the best framework for frontend?

Question

HTML

Actually, what is better to learn ZURB Foundation 5 (with SASS) or Twitter Bootstrap 3 (with LESS)?
I planned to dive into Bootstrap, but I came across a completely reasonable opinion that Foundation would be better for the front-end.
I myself have never worked with either. I'm not even familiar with preprocessors.
I am only engaged in layout and I understand that it is time to choose something. Then I plan to make up Wordpress themes.
I would like to hear the opinion of experts.

Answer 1

Frameworks for different tasks.
In general, if you are building a regular website or a WordPress theme, then they are not needed at all.

Answer 2

If the question is in Less only because of bootstrap, then here is their port on sass getbootstrap.com/css/#sass
I am for sass/scss

Answer 3

sass + compass + haml(rails)
e.g. gradient
from

background-color: #ffffff;
@include filter-gradient(#ffffff, #e5e5e5, vertical);
@include background-image(linear-gradient(top,  #ffffff 0%,#e5e5e5 100%));

in

background: #ffffff;
background: -moz-linear-gradient(top,  #ffffff 0%, #e5e5e5 100%);
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#ffffff), color-stop(100%,#e5e5e5));
background: -webkit-linear-gradient(top,  #ffffff 0%,#e5e5e5 100%);
background: -o-linear-gradient(top,  #ffffff 0%,#e5e5e5 100%);
background: -ms-linear-gradient(top,  #ffffff 0%,#e5e5e5 100%);
background: linear-gradient(to bottom,  #ffffff 0%,#e5e5e5 100%);
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#ffffff', endColorstr='#e5e5e5',GradientType=0 );