Recently I have re-discovered a framework that is reliable and stable, Gantry 5.
The first time I tried using it I was confused by the names of the components that comprise the framework such as; particles, atoms, etc. One day I had a little time to really take a good look at what this was all about. Basically there is a layout of empty cells that hold particles, which can have Joomla modules or Gantry's or other 3rd party pre-built assigned to each cell, simple.
Becaue of the flexiblity designed into the framework I was able to reproduce my clients sites almost exactly as they were before. But with a framework that was responsive and fast.
I have not received any alerts from a client reporting that there site looks weird on a phone or table device. So, I have been converting my clients sites over to this framework and have not gotten any delta feedback.