@grgarside I haven't. Not running El Cap yet because I need stability for work, but I'm sure I'll get in a spare machine around here this fall. Part of the Chrome crutch is just familiarity though -- Firefox has great debug tools, but Chrome is the old friend, so that's where we go.
@IanC. I know the feel; I tried to use Chrome's dev tools a while ago because I knew of the increased functionality but I quickly missed all the nuances of Safari's. Plus the iOS device integration in Safari is a joy!