This ARN story hints at why IBM must transfer all its key PC staff and senior execs to Lenovo:
If the ThinkPad evolves into just another notebook, or devolves into an inferior product, IBM will have damaged its reputation and brand among corporate customers, Baker said. This could hurt the software and servers businesses that IBM is trying to enhance.
Update: The NYT (sub req.) picks up on the same branding angle:
The complex transaction is meant to serve as a bridge between very different companies from different cultures, by seeking to ensure that I.B.M. has a stake in the Chinese company's success. Whether in the United States, in China or anywhere else in the world, such a stake would be in I.B.M.'s self-interest; a messy exit from the personal computer industry could rankle corporate customers, hurting I.B.M.'s other businesses, and tarnish its stellar brand name.