Yeah, i wouldn't say thinkpad's are better construction, they are just a different market. I would agree that they would have a higher mean time between failure, but i don't see the construction is better to the higher end ideapad's. ideapads have more interesting configurations, thinkpads have enterprise "features".
At work we used to use thinkpads before switching to dell, the difference is night and day between the two, thinkpads where/are just so much better. My ideapad pro has very good construction and configuration for the price i paid, except i dont understand why they put such terrible speakers in it given the feature set/quality of everything else.
i feel this review is pretty representative