For me, and I work in IT so I understand I might not have the most common perspective here, I would much rather a progress bar indicate that it is working, and, ideally, why it's hanging.  I have done installs, where it gets to 83% then hangs for THIRTY+ minutes, then installs fine.  I've also done similar installs where it seems to be going fine and then hangs for 2 weeks... knowing what specifically it's working on, or was about to be working on, makes it WAY easier to make the call on whether or not it's actually completing or not, even if you normally hide that data behind, say, a little drop down arrow.