I guess you have enough answers, but I agree with the others. It's a very, very buggy app. It does the important task that it promises so we all love it despite its flaws. But if this was a commercial app, the rating would probably sit somewhere between 1 and 3 stars.
And again, as I said to others, the idea that F-droid is not updating itself is almost self-evidently false, the issues people have reported with not being able to update apps involve some elementary conceptual errors that are being erroneously attributed to the app that have been explained by some comments here, and lastly subjective reports from people in a comment section are not a sound basis for generalization.
