I regularly read HN, and I like to think I'm generally aware of web development stuff, and I hadn't even heard of Bootstrap until the for/against argument blew

I regularly read HN, and I like to think I'm generally aware of web development stuff, and I hadn't even heard of Bootstrap until the for/against argument blew up on HN over the last few days. If I haven't heard of it, none of my friends have. Out of the hundreds of people I know, I'd imagine possibly one of them has heard of Bootstrap. Unless your startup target is web developers, nobody will have any clue what you're using as your UI kit, but they'll be pleased when things are where they normally are.