This thread has now been closed to direct all further updates about this release onto the latest announcement:
Please see https://releases.xamarin.com/beta-release-15-2-preview-2/ for the details about this release, including the steps to update or downgrade as needed.
These latest Beta versions are now also available in Visual Studio 2017 Preview as part of the May 3 update (26430.01 – Preview). The Xamarin.VisualStudio extension 18.104.22.1689 in this Visual Studio 2017 Preview is one small edit behind the version in VS 2015.
Using the latest Visual Studio for Mac Preview with this release is encouraged, but you can also continue to use Xamarin Studio if you prefer.
Please file a quick bug report using the "15.2 Preview" new bug form if you see any suspicious behavior in these versions that you wish to report.
Comment in this forum thread if your question is not related to a suspicious behavior after download, but instead one of the following:
EDIT Apr 26: Add information about VS Preview 15.2 (26424.02 - Preview)
EDIT May 03: Update link to Release Blog post for new versions.