I think the Lenovo build is great, they really did a good job maintaining IBM build quality. The Tx lot might be more bombproof than the Xx series, but I don't know - I haven't had the glorious chance to play witht he x201 / x301 at any great length. When I have, they felt a lot like really light and skinny versions of their bigger cousins, with the same great quality and strength. But, I might imagine that just because of the compromises to make them more road-warrior friendly, they would be a bit more fragile.