SkillScore should help to quickly find out if Players have some experience in specific Raid Instances by evaluating Achievements/Bosskills and breaks it down to a normalized number which shows up in the tooltip.
Get detailed information by pressing <CTRL> (default key can be changed via SkillScore addon menu)
Maximum score you can get for each raidzone is 1000.
Intended to be as lightweight as possible in terms of CPU and Memory usage.
-> updated the code for Cataclysm with some tweaks
-> removed ICC data and added Dragon Soul
-> after the score, added also the number of normal/heroic kills on the tooltip
-> couldn't figure out how to separate the number of normal kills from LFR kills, to know if the player has killed normal Madness check if he has the achievement "Destroyer's End"