I love Sketch.
As a tool, it has made my workflow a million times better than everything that came before. As a company, they have been nothing but supportive and helpful over the years as the community continues to demand new features and fixes.
But symbols...oh, symbols...Those have been the bane of my existence for the past year or two, to the point that I couldn't use them at all despite the potential value they provided.
But it looks like things are about to change for the better - the Sketch 3.7 beta introduces an overhauled symbols system with nesting, easy text overrides, and more. The video below should get any UI designer excited about how much faster their workflow might become with the update (hover to play):