I have an Earvana on my Les Paul and have no tuning issues. Unfortunately I can't offer a before/ after comparison as it was already fitted when I bought it. My only gripe is the sharp edges - when you're playing live in an adrenaline/ sweat fuelled situation and you slide down the neck, it's a bit painful when you catch your hand on it.
you wouldn't use the meat knife on crusty bread but, equally, the serrated knife and straight edge knife aren't going to go through raw meat as quickly