Here is a list of what we are loosing when moving to !GitHub:

  - no private branches (where we'll put our repository for papers?)

  - no private wiki pages (where we'll put our todo list and referee comments?)

  - command line unfriendly behavior of the !GitHub download links for .zip and .tar.gz files
    - here is how it works currently:
{{{
wget http://cp3.irmp.ucl.ac.be/downloads/Delphes-3.1.2.tar.gz
}}}
    - here is how it works with !GitHub (command is almost twice longer and with additional parameters):
{{{
wget --no-check-certificate https://github.com/delphes/delphes/archive/master.tar.gz -O delphes-master.tar.gz
}}}

  - no search in wiki pages (github proposes to do it from command line using grep)

  - limited code browser (for example, no way to compare old and new versions of the same file, and yes, I regularly use this functionality)

  - no way to adapt to our needs the interface of the code browser, wiki pages and issue tracker (for example, currently it's difficult to switch from code browser back to documentation)

  - some information (formatting, dates, users) will be lost after migration of the tickets from trac to github.

  - backup of github code repositories is more difficult (needs manual intervention for any new repository)

  - backup of issues/tickets is even more difficult

  - restore from backup is not clear at all