I don't know if it's Adobe Reader 9.4.7 for Linux, or the way it interacts with KDE 4.7 or some other aspect of Debian-testing at the moment (the moment in question being the last few months), but....
Saving files is sloooow. The save-file dialog comes right up, more or less, but doesn't accept clicks for quite some time. The application appears frozen (I can drag the dialog box around, and the display doesn't update behind it), but isn't consuming much in the way of CPU cycles.
Printing is likewise slow, though not to quite the extent. Again: dialog box pops up, then there's a long wait before anything is clickable.
I mainly notice these when it's been running for a while, and I've opened a bunch of tabs. Since the tabbed interface is my main reason for using the Adobe product instead of something open-source, so I can keep a bunch of datasheets and standards documents open and handy, this is the usual situation.
Oh, and speaking of the tabbed interface: it's gone funny, as have other bits of the UI. Focus keeps getting lost or reassigned. I have to go through weird sequences of clicks to change tabs, select the menu bar so the tools will activate, and restore focus to the document so the scrollwheel will scroll the document view instead of, e.g., switching tabs.
All this is stuff that Used To Work. And it's not like other apps (including commercial ones) have similar problems on this system; they all behave themselves.
It's almost like Adobe has become a big established company, with no need to concern itself about whether its products actually work. Next step: becoming a government agency.