I have quite a few frames in the same size range, built with Reynolds, Vitus and Columbus double-butted tubesets. I also have a "lesser" frame constructed with seamed tubing. It is not poorly constructed, by any means. While it's not pretentious, it's clear that whoever constructed it used care; that's what appeals to me about it, and makes it one of my favorites. It weighs as much as 600 g more than my lightest frames of the same size; but only 400 g more than a Peugeot PX10, or a Serotta Club Special.

So, not that much difference in weight. There might be more difference in ride quality; and I grant that the the lighter frames provide a livelier ride. But I've decided that this isn't everything in a frame, for me, when all is considered.