It really just depends on the the dungeon and bosses mechanics that you are doing. Hlr lb's are totes needed for like WOD's cloud of darkness and generallly any 24 man raids at release. The DPS DoM lb is great to use when there are a lot of enemies alll bunched up and RNGD DPS lbs are great just because of their range. And, Melee DPS Do the most damage, so basically it's best used when You have to do DPS checks on single targets. Basically everything is as simple and easy to understand what to use what lb and when to use it