I started with and continue using the standard Weaver stance. For me it's all about comfortably and quickly getting to my natural point of aim. I do that best with the Weaver. I'm right handed and right eye dominant so the Weaver stance drops my eye right in line with my sights without much effort.
I struggle to get comfortable with the modified Weaver and especially the isosceles. The isosceles really messes up my aim for some reason.