I had some problem with Grid. When lots of raid change their "alive" or zone status (for example, by pressing "Release spirit" button after a wipe in Tempest Keep simulateously), I had a strong lag, for about 5-10s I'm unable to do anything, WoW just freeze :(
This problem persists for about two months, Grid is being updated to last rev regulaly.
Unfortunately I cannot specify Grid revision right now 'cause it is installed on home PC.
Another problem is DCs, caused by addons. I suspect Grid again because of it's communications with other raid members's addons :(