For me it has been hit or miss. About 50% took the update and the others ignore it. Then 1.1 Patch 1 came out and I'm having the same experience with it, about 50% have taken it as well. I'm seeing this same behaviour with Agent adoption too where about 50% of the machines don't take new Agent versions either. Oddly the machines not getting agent updates is not the same set as those not getting the AV updates.
I finally resolved my issue once I realized our machines were running MSM 1.1.1303 (18.104.22.16873) and the new Patch 1 only works with MS 1.1.1309 however. I used ePO to uninstall the older version and then had them pick up the new version after installation which then allowed the Patch 1 to deploy which results in 1.1.1418 = 22.214.171.12424 being installed.