Devs win when Sourcegraph and GitHub compete. And yes, Microsoft/GitHub will compete fiercely with us--and we'll compete back. Devs should cheer on the competition, rather than let Microsoft/GitHub get complacent.
There are 2 situations where Sourcegraph shines:
1. When you use something many times daily, then you need/deserve the best. We're 100% focused on being 100x better: speed, precise/cross-repo code nav, comprehensive result sets, all branches/commits, more code metadata, all code hosts (GitLab+Bitbucket+any others), way more languages, batch changes, insights, etc. GitHub's code search will be a good place to start if you're new to code search, but Sourcegraph is and will continue to be better for devs who rely on code search frequently, which in my experience is most devs once they get hooked on code search. :) (If we aren't much better than GitHub code search, we don't deserve to exist. Please give us direct feedback on how we can be better--the more competition Microsoft/GitHub feels, the better for everyone!)
2. For companies whose needs differ from what GitHub's core userbase wants, such as self-hosted deployment, single-tenant/managed-instance cloud deployment, massive codebases, numerous repositories, many languages, many code hosts, custom integrations, heavy API usage, etc.
Whether you use Sourcegraph or GitHub, we'll keep improving Sourcegraph to keep up the competitive pressure on GitHub to continue improving their code search. Everyone wins. :)