First check the travelling weight of both systems, assuming you will be dragging a laptop from place to place frequently.
Second, determine how long you need the machine to last before your personal needs exceed its technology, ie before you will insist that the machine you buy today is no longer as fast or light or nice as a new machine. Personally, I consider laptops to be a "disposable", ie to be used for no more than 3 years and then resold as whatever price the market will bear and then buy a new one. Since they usually cannot be upgraded incrementally (like desktops), when the latest operating system and office software demands greater speeds and video, it is easier just to buy a new one. If that is your expectation also, then the build quality is less important than the price. After all, if it breaks after 2.5 years and you planned on replacing it at 3 years, you have not lost much. If you plan on keeping it in service for more than 3 years, then by all means buy the IBM for its quality. Like a new car, once they are a few years old, the depreciation is so great that they become a commodity. The IBM may have a greater resale value, but may cost more initially, too. Just my opinion.