I would like to inform you that the Bootstrap v3.3.7 grid css only is just 13kb including Normalize!
The Bootstrap v4 grid css is about 30kb.
As far as I know with the Bootstrap grid css you can do everything or more you can do with Unsemantic, with less classes (while it’s mobile first, Unsemantic isn’t).
BS is working well, well documented, very popular so many people know the classes to use and it is even quite lightweight.
So perhaps worth considering for the future? 🙂
Mark