Finally had a chance to test it last night in a 40 man PvE raid. Molten Chore to be exact
. Never had any issues aside from when people were added/removed from the raid while in combat (that's a secure frame issue, not a mod issue, I know).
I really can't wait for some layout options since the current default layout is just too much open (read: wasted) space and just some more configuration options. I also didn't try out showing mana bars, which might be a nice built in feature eventually.
Functionality seems fine, just the nitty-gritty formatting that could make it great. But I guess we'll have to wait for Blizzard templates.