Show downloads denied with 'too many files' or 'too many megabytes' as queued and automatically requeue them every so often.
See the Changelog for list of features and fixes currently only available in the nightly builds.
Though most of you would probably find the update notification to be the most useful new feature of tonight's build, most of the work went toward implementing user-initiated uploads, seeing as those had to be made to work in both directions if the feature were to be considered complete. To attempt to send a file to a user, right-click their name and select 'Upload to user'. A share browse window will open showing your own files, or at least what subset of them should be available to the particular user based on your shared folder privacy settings. The functionality here should be identical to that of a typical share browse window, with the exception that download operations are replaced by their upload counterparts. Whether the user will accept your upload entirely depends on their own client upload acceptance settings, which are handled differently in SoulseekQt now that it has them. A checkbox under Options->File Sharing will allow you to accept files sent to you from anyone on your user list. To only accept files from specific user groups, use the group configuration control available under the Users tab.
Update notifications should be a no brainer provided that they work properly. I guess we won't know for sure until the next release :D A popup will inform you when you open SoulseekQt whenever there's a new version available. If you do not feel obliged to update, you can use the 'Skip' button to make sure you're not notified again until the next update.
Finally a button at the very left of the action bar will allow you to toggle your away status. The away status of other users will also textually show up in any of their private chat windows.
A few other small things:
Fewer than I imagined. Links on the download page!