The hardware on thinkpad's lean toward Intel motherboards, chipsets, cpu's and integrated graphics. Thinkpad's also have superb build quality.

I believe IBM conceived the thinkpad and nurtured it trying to engineer a solid product for corporate world. Retaining customers and creating a perception as a safe choice fit with IBM's ideals.

I believe dell put salesmanship slightly ahead of creating a reliable device. Gateway and HP opted to make a shiny chassis, cheap hardware substitutions, difficult to maintain and subsidized with shareware.

At the end of the day, I do believe Lenovo carries on the thinkpad visage of being a safe choice and not cutting corners like some of the competition.