Well, I already have a business class HP machine (tc4400, not my choice), and the build quality is terrible on it, too.
I'm inclined to trust Lenovo on build quality more. Apple is mostly pretty good on that, too, since it seems like all of their high-end machines are built to a higher standard. Of course, Apple has made some bad design choices, so you have to be careful, but I think the current MBP is a fairly well proven design.
My requirements are a bit tricky to balance, since I need something relatively portable as well as powerful. That's where the MBP seems to fit well, but I'm not sure how portable this Lenovo is (I haven't gotten to handle one yet).