Great question! I personally prefer to use Sass because I really like a lot of its features that make writing CSS easier. As far as frameworks, even though frameworks such as Bootstrap do have a place in some settings, say a large company with 200+ devs, I think they're overused. They can be good, but I think that the front end developers working with frameworks need to also know how to do everything the framework does so they don't always have to rely on that framework to be able to code responsive sites. I kind of think that might be why they're so overused. I prefer to code responsive sites without a framework so that I'm not tied down to its breakpoints, but at work, since I work for such a large company, it makes sense for them to take advantage of Bootstrap's grid system.