GIT is good to be used for faster and high availability operations during code release cycle. Git provides a complete replica of the repository on the developer's local system which is why every developer will have complete repository available for quick access on his system and they can merge the specific branches that they have worked on back to the centralized repository. The limitations with GIT are seen when checking in large files.
RubyGems is a great packaging library primarily because of its verbose logging information and easy to navigate system architecture. We've dealt with artifactory systems in the past for Java and JavaScript, and RubyGems just makes it a lot easier to handle the packaging and deployment of our reusable libraries. We've noticed in the past that there are times where (if all 200+ teams) are releasing at a similar time that publishing the gems can lag, but that's fairly rare.
Git has met all standards for a source control tool and even exceeded those standards. Git is so integrated with our work that I can't imagine a day without it.
I am not sure what the official Git support channels are like as I have never needed to use any official support. Because Git is so popular among all developers now, it is pretty easy to find the answer to almost any Git question with a quick Google search. I've never had trouble finding what I'm looking for.
RubyGems has strong community support and finding issues to errors is as simple as searching for the error message you're receiving (but usually the error is clear enough without having to bother with that). Honestly, the framework is simple enough that support isn't needed much, but it has been helpful to us in the past when we have needed it.
I've used both Apache Subversion & Git over the years and have maintained my allegiance to Git. Git is not objectively better than Subversion. It's different. The key difference is that it is decentralized. With Subversion, you have a problem here: The SVN Repository may be in a location you can't reach (behind a VPN, intranet - etc), you cannot commit. If you want to make a copy of your code, you have to literally copy/paste it. With Git, you do not have this problem. Your local copy is a repository, and you can commit to it and get all benefits of source control. When you regain connectivity to the main repository, you can commit against it. Another thing for consideration is that Git tracks content rather than files. Branches are lightweight and merging is easy, and I mean really easy. It's distributed, basically every repository is a branch. It's much easier to develop concurrently and collaboratively than with Subversion, in my opinion. It also makes offline development possible. It doesn't impose any workflow, as seen on the above linked website, there are many workflows possible with Git. A Subversion-style workflow is easily mimicked.
RubyGems is easier to use and to troubleshoot issues overall. Sometimes when troubleshooting in other systems errors are masked and it takes a trained eye or a lot of time searching through Google trying to find out what it really means. RubyGems is very verbose and allows for quick troubleshooting of any deployment problems.
Git has saved our organization countless hours having to manually trace code to a breaking change or manage conflicting changes. It has no equal when it comes to scalability or manageability.
Git has allowed our engineering team to build code reviews into its workflow by preventing a developer from approving or merging in their own code; instead, all proposed changes are reviewed by another engineer to assess the impact of the code and whether or not it should be merged in first. This greatly reduces the likelihood of breaking changes getting into production.
Git has at times created some confusion among developers about what to do if they accidentally commit a change they decide later they want to roll back. There are multiple ways to address this problem and the best available option may not be obvious in all cases.
