https://yukari.sr.ht/aerc-intro.webm
Don't repost this, please, the official aerc announcement is coming in a few weeks.
I'm working on making a UI similar to GitHub's for reviewing patches which is built on email underneath, but can be used entirely on the web. The first step of this became available a few weeks ago, and now email threads are being rendered into a review UI which is similar to GitHub's with inline feedback and such:
https://lists.sr.ht/~philmd/qemu/patches/5556
This page is fairly new and still needs a bit more work towards mobile support, but I hope that gives you some more confidence in the platform. I intend to extend this so that you can also review patches from the web, which will generate emails on the mailing list, and prepare patchsets from the web as well. The end result will be a UI which is remarkably similar to GitHub in terms of usability on the web, but is backed up with distributed technologies and seamlessly integrates with the workflows of devs who would rather use email.
On the whole Sourcehut is actually quite a bit better at responsiveness than GitHub, too. Rather than a dedicated and inferior mobile site, almost all sr.ht pages are responsive and equally capable on all form-factors.