Although not a formal survey, I would add that GVR has been spreading (not scientific) on weekends 1/2 NL, and for limit, 2/4, 3/6 limit, and sometimes 4/8. Usually there are 1 or 2 tables of each except 4/8 doesn't run so much since 3/6 started being spread. As far as I can tell GVR has basically (for the moment) 'won' the locals over from the M, and hardly any games are going at the M these days. Not sure what happened there.
Have you considered using the Bravo poker live to get quick surveys?