How secure is PPTP?

[dnewman () data com]

Aleph One recently noted that "PPTP can be make to leak part of the bit
stream. The next version of L0phtcrack will also crack the PPTP c/r. On a
fast machine a brute force can take as little as a few days."

Given the potential for memory leaks, and the recent release of L0phtcrack 2.0, 
what are the issues for current or potential users of PPTP? 

Regards
David Newman
Data Communications magazine