I agree with most everyone else. I am a raid/guild leader and I encouraged a lot of my guildies and friends to get this addon, specifically for the pre-fight explanations. I have a couple of "those guys" that just can't seem to understand my directions as I explain positioning on the boss. Obviously, it gets hard to run around and show where to stand.
For example, blood queen. Before AVR we had to do a little sit and talk (where in the middle someone would shout "LEEERROOYYY JEENKKINNS" naturally) as I explained positioning, but would always *somehow* create confusion. When we got AVR, I was able to draw circles and color code them to show who stands where. This cut down on a lot of frustration from miscommunications or understandings, and made my life as a raid leader a lot easier. I agree with others, it would be fantastic if I could somehow draw or mark spots that would "disappear" in combat. Or, if they would give us more flares that could be created with wotlk mats that would make me happy too.
"If the tank dies, it's the healers fault. If the healer dies, it's the tanks fault. If the dps dies, it's their own damn fault!"