I have been using the RCN Synergy Remote for years successfully. After the plug-in update roughly 10-2-2012, that remote no longer works. I switched to the Comcast C1116 for DCH3416 boxes and that works. But it has far fewer buttons and I constantly use many of the missing buttons.
The RCN remote downloads however when I click the button to show it, only a white square appears on the screen. And with this remote selected, often the plug-in will freeze trying to connect to my Slingbox Pro-HD.
I run OS X 10.6.8 Chrome 24 but also tried Safari 5.1.7 and it fails with both.