I'd compare this to [Bourbon Neat](http://neat.bourbon.io/) (which I've only looked over) and [Foundation's grid](http://foundation.zurb.com/docs/components/grid.html) mixins which seem to be much more flexible and offer the ability to use columns without rows (and no "container" required) allowing for a much more "semantic" results.
I spent a lot of time trying to decide between Bootsrap, Foundation and Bourbon + Neat recently and in the end had to settle for Foundation for the following reasons:
* Has decent default typography settings (not available with Bourbon + Neat though Bootstrap's is fine)
* Much better Grid than Bootstrap (though I think I may like Neat better)
* SASS not LESS (all my current work is in SASS though switching wouldn't be all that painful)
I say "settle" because I think so much of Bootstrap's styles and UI components are superior. Particularly the forms, but also progress bars, badges, labels, navigation, menus are all nicer.
Right now I think what I'd love to have is a set of extension defaults for Bourbon + Neat that bring in nice styling for forms, buttons, typography, etc. In fact I'm half tempted to just copy it all from Bootstrap. Who knows when I'll have time to do something like that though.