What are best practices for reusing blocks between sites? What's the best way of reusing blocks between sites in Drupal 7? I want to re-use not only the block, but also the block's position in my theme. 

Apparently, Features extra is designed for this. However, on the project page, it says that UUID Features Integration is the future of the module.

UUID Features Integration, however, doesn't seem to work (although a patch is available to fix things). Also it has been dropped in favor of Deploy.  

Deploy, however,doesn't seem to work with blocks and is designed more for exporting nodes. So, I'm not really sure how it is a replacement for UUID Features.

What is the best practice for what I want to achieve? 

PS. this is a new version of the question "Latest Best Practise: Reusing content/functionality between Drupal 7 sites", as I was told to post it as a separate question.
Page Manager, Panels and Features.

The plugin architechture in Ctools, which is the project in which Page manager belongs, is the best way to re-use blocks, among other things.

All my block placements are done with Panels, and then exported to code with features.