Hi everyone,
It appears as though the discussion has continued apace for the Gerrit evaluation process: http://www.mediawiki.org/wiki/Git/Gerrit_evaluation
Thank you everyone for chipping in so far. The current format is a mix of talk page and structured discussion, which seems ok for now.
It would appear from reading this page that the only alternative to Gerrit that has a serious following is GitHub. Is that the case? Personally, it seems like Phabricator or Barkeep has the best chance of dislodging Gerrit, but those won't probably get serious consideration without a champion pushing them.
Rob