I don't know about the modern ones. I've been a thinkpad user since 2005 or so and my impression is that the quality has been dropping consistently. Traditionally though, many of them came with a magnesium alloy roll cage that protected the internals quite well. It considerably reduced flex and made the whole thing quite solid. The X1, it seems, has a carbon fibre roll cage. I don't have any personal experience with it http://www.lenovo.com/us/en/thisisthinkpad/innovation/roll-c...