I more or less know all the answers for LaunchDarkly (except pricing details), and for the internal feature flag service we're deprecating, but I haven't gone through and answered it for all the other offerings. It would be time-consuming, but very useful.

Also, undoubtedly contentious. If you want an amusing read, go check out LaunchDarkly's "comparison with Split" page and Split's "comparison with LaunchDarkly" page. It's especially funny when they make the exact same evaluations, but in reverse.