The latest download pack for Mass Effect called Pinnacle Station, is experiencing quite a few glitches. So many in fact that it’s having a significant impact on the gameplay. A lot of people are posting about problems on the message boards and Bioware is aware of it and will fix the glitches soon.
If you are still undecided about purchasin Pinnacle Station, I would suggest you hold off for a while, at least until Bioware fixes these problems.