[piotrkaminski]

This looks like a good spot to plug Reviewable (https://reviewable.io), which addresses the disappearing / untracked comments issues and more, while still integrating with GitHub rather more gracefully than something like Gerrit. While GitHub's PR review tooling has improved in the last year there's still a fundamental difference in philosophy such that Reviewable isn't lacking for customers. :) (Disclosure: I'm the founder.)

[danpalmer]

I've looked at Reviewable several times, and I'm afraid to say I've never been convinced to try it. There's obviously a huge cost to moving team process over to a new tool like this, but also I just found it more difficult to understand what was going on compared to GitHub reviews, so it wasn't particularly compelling for us. Hope you don't mind the candid feedback!

[piotrkaminski]

Feedback is always appreciated, and candid feedback is highly prized! I get what you're saying, but it's a fine line to walk: if Reviewable is too much like GitHub, it won't be able to add sufficient value to be worth using. If it's radically different, few people will be able to figure it out at all. I'm happy with the balance I've hit but it's definitely not for everyone -- on either end of the scale! Also, there's a forthcoming migration from Angular to Vue where I intend to make major changes to the UX, which will hopefully increase usability and make onboarding easier... We'll see!