With much improved Domino Designer speed (oh, and that is now free and will be available later today) and literally tons of fixes and enhancements, 8.5.1 is THE release to be on.

It is available on IBM Passport Advantage. As of writing you had to go to "View all my downloads" under the "Download finder" tab. Expand then look for 8.5.1.

FYI, the admin client is included with the Designer download, called lotus_dominodesigner_w32_CZ5S0EN.exe.