Apparently one of our readers discovered that when he updated to the new Acrobat Pro XI the program lost track of his designated default printer. Now, Acrobat seems to present his printer options in alphabetical order, rather than the one he has chosen as his default printer. This issue was reported on the Adobe Community forum, and a response from an Adobe team member acknowledge that it was "a genuine issue" and they have logged a bug report. So presumably this annoyance is more of a bug, and it will hopefully be corrected soon.
If you have any annoyances, let us know by emailing me at email@example.com. We're looking more for UI problems, than for bugs, but we appreciate any feedback to help make Acrobat better.