Bootstrap is pretty great, and I'm very familiar with it because I've worked with it so much, but I am also inclined to be discerning about when it's used.
For example, the site you're currently on uses Bootstrap, but I only used it because of the low traffic. It's also a great way to build something that looks good right out of the box. If there is a lot of traffic, and speed is a concern, I might recommend building everything from scratch since Bootstrap requires a lot of libraries that can slow a site down.
Mostly I wanted to include it here as a way to show that I am very familiar with it for those employers who have it in place already, but there are employers who view Bootstrap as a kind of cheat, so I need to show that I am aware of its limitations and drawbacks.