The problem I have with all these self-promotion frameworks (i.e. CSS frameworks open sourced by commercial entities) is that they are inherently at the mercy of said companies.

Take Zurb Foundation for example, as far as I can tell its basically become abandonware. Foundation 7 has been promised forever and yet we're still stuck with Foundation 6 which has all sorts of bugs and gotcha's that will catch people out because the framework is out-of-date in comparison with the technology that people are using to access websites.

The only exception to this is Twitter Bootstrap which has been consistently kept up to date. Whilst I don't agree with some of the design decisions in the latest Bootstrap 4, it remains a solid, well maintained framework.