Hackernews and LWN render reasonably correctly in recent nightlies. Reddit does not.
Edit (with Firefox): the above text is from Verso. Logging in works (though the session is not stored across restarts), as does both commenting and editing comments. Since space can't seem to be entered, word wrapping doesn't work with text entered in Verso, though it does seem to work when there is text with spaces (eg, this edit). A cursor also doesn't appear for me, making editing a challenge.
This is most likely a server “feature” and thus a rewrite of the frontend won’t fix it but it seems like at very least the frontend could display a sane error message (assuming the backend forwards some information about the cause of the error).
At least on mobile.
Reddit: Wait no.