Well whatever css framework pair up with whatever shouldn't be your long-term viability concern. Front End technologies changes too fast. IE. for the mainstream, couple years ago everything is jquery, than comes backbone, ember, angular, now react.js and than maybe riot.js. When Angular 2 releases stable version, it probably shift it again.
Your questions should be which ever framework help you do YOUR JOB quicker. Different clients might want different things, some clients i dealt with uses Bootstrap, they provide their corporate design patterns and some of their reusable jQuery * bootstrap widgets to implement, some gave me backbone models and ask me to use it in an angular as an angular service. And some asks me to do it in stylus instead of sass.
So pairing up css and js framework isn't any of my concern for long term, the trend changes too quickly. And the good thing about react is that you can bundle all these third party libraries into one single component ( if you really want do do that. Eg; embedded css into complement with react-styles, if some of your component uses jQuery, you can do a script lazy load at componentWillMount life cycle. ), you got the total freedom, if some strange case that you want to uses both foundation popup and bootstrap popup together on the same page, you can write your own react components to wrap one of each, as long as you got the scope well managed.
Which ever css framework you use as long as it saves you time to do things is beneficial, there isn't a best one, my team built our own css and js framework on top of any libraries to tailor it for our job.
