I currently am mix & match..& it's a budget thing. But I think that the truly great designers build their components to mesh with one another. Everything is considered from input to output of one component connecting to the next. I can remember listening to the designer of SW1X audio go into great detail about how he focuses on component matching..even between the lower & upper line of his products. It made sense to me.
But a lot of times you just want the best for your money. And that means mix & matching. Getting a new piece & hope it pairs well with what you already have. Obviously there are many great sounding systems out there..all 1 manufacturer or 5 different.

