If you have the latest updates, then Acrobat Reader 9.4.2 does (at least) partially work in Ubuntu 11.10 + Unity.
There are a number of minor glitches - due to changes in Ubuntu's undelying GUI, kernal, etc. in the upgrde to Ubuntu 11.10 (Oneiric).
- floating scroll bars (only appearing when you hover mouse-cursor)
DOES NOT WORK: Does not scroll page ..
You may need to disable this feature. (in CCSM)
- Edit >> Preferences
This tries to work, but loses focus. I can see the Cancel and Ok buttons, but they don't do anyhting.
This is a GTK+ library issue, and an update to 9.4.2+ is needed.
Summary: There are a number of minor GUI issues that haev existed in 9.4.x for Linux. The update to Gnome 3 and Unity (for Ubuntu 11.10) has definitely made this much worse.
I just found that you can, in fact, make changes to the Preferences using the keyboard. Use <tab> to move between selections, <spacebar> to select or unselect checkbox options, and <arrow> keys in spinners. To finalize, select the OK button using the <tab> key and press <enter>. It appears you have to pres the key a few times, or maybe there is a delay and I was too impatient.
Hope this helps.